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Chevy Suburban/Tahoe Rough Idle and Stalling

245

Comments

  • pear69pear69 Member Posts: 20
    Did you install AC Delco plugs and wires? If not you are wasting your time. AC Delco ignition parts are the only parts that work on Chevy engines. I know they are more expensive but that's just the way it is with the high voltage Chevy ignition systems.
  • elorenzo39elorenzo39 Member Posts: 20
    I have this problem not too long ago on my 99 Suburban after the intake manifold gasket was replaced. I have a good all buddy helped me out on this forum. I bought a non ac delco parts and nothing has change, but when he suggested to replace it with ac delco, the truck ran better. I had a rough engine and showing a code of P0304 misfire on cylinder #4 and a blinking ses light when at a speed of 35 - 45 mph. California vehicle had a special warranty up to 200k mile on their fuel injection system and dealer checked and replaced. Car runs great now.

    I did not catch the whole story. Please provide me some symptoms that you are experiencing and what year and type. I will share with you some of my experiences.
  • elorenzo39elorenzo39 Member Posts: 20
    Did it give you any codes?
  • alanrsalanrs Member Posts: 25
    Having a problem with my Suburban, began at a little over 80k miles. SES light activated on interstate at 70mph while towing an empty trailer. Filled up with "better" gas, light out within 50 miles. Light back on within 100 miles, showing a 300 DTC. Cleared code a couple of times, returned as 305 or 300. I figured it was time for a tune-up, replaced plugs and wires. [Note: OEM plugs were DENSO platinum type]. New plugs Iridium, 0.60 gap as specified in manual and engine compartment sticker, new Delco wires. Rough idle still present, 305 code returns after clear.

    Have since changed/tried: New fuel filter, swapped coil units beween cylinders, sprayed brake cleaner around intake (as leak detector). No change. Removed and sent injectors for professional cleaning. Still no change. I broke down and took the Burban to the dealership. $184 later, and no diagnosis of the actual problem. They say electronics and fuel system are ok, performed leakdown test, with no issues. Wantd to "disassemble" top of engine suspected "grooved camsaft" or other valve train issue. I declined permission to take the engine apart.

    Would be happy for any advice I can get at this point.

    Thanks
  • elorenzo39elorenzo39 Member Posts: 20
    Please tell me what year, what code does it have. What state are you in. I had the same problem before and I was showing P0304 cylinder 4 misfire. Let me know. Check compression on each cylinder while the SES light is still on. My Burb did that for 1 year and the problem on mine was the Spyder injectors that was replace for free in the State of California and is waranteed up to 200k mile. A month later it showed up again P0304 and my compression was dead on that cylinder. I ended up getting the engine replaced then sold it due to high gas price in California.
  • alanrsalanrs Member Posts: 25
    I am in Michigan. The code is 305. The engine passed compression and leakdown tests. This is a 2001, injection has fuel rails with individual port injector units, and a plastic composite intake manifold.
  • pear69pear69 Member Posts: 20
    Try changing or swapping out number 5 cylinder injector with another known good injector. P0305 code is cylinder 5 mis- firing. Denso plugs are ok for these type of coil/over ignition systems but A/C Delco are the best. What is the fuel pressure? Did you check the TPS sensor?
  • alanrsalanrs Member Posts: 25
    The injectors were removed, tested, cleaned, retested, and yes I re-installed with 2/4 and 3/5 in different locations. Injectors are not the issue. The Denso plugs CAME in the engine FROM GM. I was surprised too...... I replaced with Autolite, only because they were only ones I could find with the specified 0.60 gap in an Iridium type. #3 and #5 coils were also swapped. Tech2 showed no issue with TPS, and I get consistent readings from it on my scan tool as well. Dealer says there is no electrical or fuel issue, and BTW, I measured fuel pressure between 46 and 50 PSI.

    The Tech2 showed a misire history stored in the computer that was heavily at cylinder 5 (over 50,000 the day we read it), with way too many (but about 1/10 of cyl 5) on cyl #4. Others showed single digits or zero. I wish I knew of someone with an engine smoker in my area, so I could check the intake gaskets.......

    This is perplexing. I love this truck, and am bummed that it is running poorly. Been driving for 40 years, his is the first time I have had any issue like this. I run most of my cars/trucks 150K miles or more with no engine problems. :(
  • pear69pear69 Member Posts: 20
    Your fuel pressure should be 55 to 66 psi. Make sure the fuel filter that's attached to the fuel lines is new and installed properly (this filter is directional). If this filter is good then the filter that attaches to the fuel pump (inside of the tank) is probably dirty. This filter ( I believe) is not serviceable. I suggest replacing the fuel pump. When replacing the fuel pump on these chevys it is VERY important to replace the fuel pump chassy harness connector ( this is the electrical connector that plugs into the fuel pump). This connector is a one shot deal -- meaning that it can only be plugged in and out once -- because of a design flaw. Failing to replace this connector will cause the pump to shut off and/or arc creating the potential for a fire. Also, the ground for your fuel pump is connected to the frame close to the fuel tank -- find this (black wire) ground and disconnect it and clean the area around it real good and then reconnect it. This ground corrodes and it is usually better to cut it off and re due the entire connection.    This may not be the mis-fire problem but it is important to have the proper fuel pressure before you change everything else (like is seems you have done already). A code 305 is specific to a mis-fire to cylinder 5. Make sure all the wire connections are connected properly.  Pull cylinder 5 spark plug and pull another plug that is firing. Is there any difference in the appearance? What do they look like?

    I believe you mentioned that you sprayed brake cleaner to look for an intake leak. Try spraying some CRC electrical contact cleaner all around the intake--it is safer. Do this with the engine running at idle -- if the idle changes then (of course) you have an intake leak.

    Also, is your coolant low? These engines are famous for the lower intake gaskets to fail. If the coolant is low and there is no outward signes of a coolant leak, then the intake gasket may have failed inside of the engine and coolant can leak into cylinder 5 causing a mis fire. Check your oil to be sure that there is no coolant in the oil. Looking at the plugs will confirm whether or not there is coolant leaking in no. 5 cylinder.
  • arriearrie Member Posts: 312
    One thing that I was told by the GM dealer is that in general misfire trouble code does not indicate fuel delivery problems. It only tells about the quality of the spark, i.e. it measures if correct resistance is present at spark plugs for correct spark. So it means misfire code indicates electrical problems.

    Here I explain what happened to my "04 Tahoe 5.3L Flex Fuel engine very soon after I got the car. I have posted about my problems several times in this forum before but this all is very difficult to find I assume. Here are a couple of easy checks.

    1. After only about 1200 miles my Tahoe started eating too much gas. This means 18 mpg went down to 13 mpg on highway driving. During the trouble shooting process, which I had to do myself while the dealer did nothing during warranty period, I first changed spark plugs. After that I get misfire trouble codes. As I had only changed the plugs this obviously had to be related to plug change. As a result it ended up being very simple problem. Some of the aluminum metal shields around spark plug booths that my Tahoe engine have were grounding spark to engine ground. For trouble shooting purposes I removed the metal grounding spring from the end of the shields, which allowed me to even see the problem, i.e. when it was dim lighting conditions I could see a spark between some of the shields and engine parts, mostly exhaust manifold.

    When spark plug wires get old they can crack and other vice loose isolation properties and start leaking spark to the shield. Because the shield is grounded to the engine with that spring in the end of it the spark has direct contact to ground. This will lead to misfire as the resistance for spark forming changes.

    This same problem easily happens when spark plugs are changed. When the plug wires are pulled from the plugs sometimes they are very tight. This can cause the plug connector inside the boot slide out. When this happens the boot does not go over the new spark plug deep enough leading to spark leak around the boot to shield and this was exactly what happened to me. Some of the wire boots did not go on plugs deep enough and spark leak was very bad. This can also happen with new wires as all of them do not have plug connector deep enough inside the boot.

    There is very easy way to trouble shoot for this, i.e. remove all aluminum boot shields. They are used only for heat shield purposes so you can take them out and drive a few miles and see if that fixes the problem. I actually took mine out and drove for a week without them. I could smell a little burning rubber but they did not catch fire or anything. Then I went and bought a set of high performance spark plug wires for $5 less than stock wire set from dealer cost, a set that does not require using boot shields and have been trouble free from this problem since. It was not the cause for low fuel mileage though.

    If your engine does not have the aluminum heat shields around plug wire boots then above does not apply to you.

    2. This happened to me just 2 weeks ago. I was working on the car again for fuel mileage, which has been back to around 17 mpg highway but not 18. I decided to change O2 sensors, the first one in each bank. Went to Auto Zone and they had a Bosch sensor for $65.00. This sensor was of the universal type, i.e. It did not come with wire harness and I had to use the one from old sensor. Further more, the instructions in the package did not explain which wire is the signal so I tried to guess. As we all know Mr. Murphy does not take days off so my guess was wrong, i.e. it is the BLUE wire that is the signal, not white.

    But very interesting thing happened while I tried to run the engine with wrong O2 sensor wire as signal wire. I got probably all of the misfire codes the computer can give. And the engine was running VERY ROUGH!

    So, your problem could be with oxygen sensor too. It just takes a new sensor to try. There are ways to test a sensor but if you already have 80 000 or so miles on it it might be a good time to change O2 sensors anyway.

    Arrie
  • pear69pear69 Member Posts: 20
    Arrie, I agree with your analysis -- however, alanrs seemingly has access to a Tech2 autoscanner. These scanners are what the dealers use and they cost around $8000.00. A bad O2 sensor would have already been indicated. Also, an O2 sensor is nothing more than a fuel delivery device. It measures the amount of oxygen in the exhaust and tells the computer to either richen or lean out the fuel delivery. I agree that with 80,000 miles, changing them is not a bad idea -- but I do not agree that they are causing this mis-fire condition.
    This engine has coil over plug wires meaning that they are very short; the reason for this was an attempt to reduce the resistance and arc travel time to the spark plug. It was stated that the wires are A/C Delco ( one of the best ) and they are new. Yes, those heat sheilds can be a problem, but pulling the plug and looking at the condition of that plug will tell you whether or not that particular plug is firing properly -- meaning -- burning all the fuel. It will also tell you whether or not that there is enough fuel getting into that cylinder and also, whether or not there is coolant leaking into the combustion chamber....Low fuel pressure seems to be the problem in this case--but we'll just have to wait and see----
  • arriearrie Member Posts: 312
    Well,

    Just trying to help...

    I forgot to mention that when I had the O2 sensor signal wire connected wrong I DID NOT get a code for O2 sensor...go figure...perhaps thing are not always what they should be.

    Removing heat shields around spark plug boots is so simple thing to do too that I would not hesitate trying that. And sometimes thing help that don't seem they should.

    There are times when something fixes the issue that should not. I would take the fix and think later why it helped.
  • alanrsalanrs Member Posts: 25
    The plot thickens.
    Today while driving I noticed that the misfire had magically disappeared. Sure enough, smooth idle, no "chuggle" when I lift foot off of brake pedal... Of course, I expect it to return, sooner than I'd like. Will pull code(s) before next drive. SES light has been coming and going for the last few days. I am now convinced more than ever that it is an electronics issue. Was leaning towards investigating the intake gaskets, but that is not something that could possibly heal itself. As part of looking for a solution, I will probably have the PCM re-flashed.... GM friend has offered....
    I think that fuel pressure is not likely to be an issue either, since that would affect more than one cylinder, and this has consistently been #5, with a bit of #4 thrown in for good measure. Recall that I tested it with engine running, which the manual says could result in readings 7PSI below the "Key-on-engine-off value. Depending on the accuracy of my not-too-expensive gauge, 50 seems within reason, that would put the expected static reading at or above 55.
    There is no side-arcing from the plug wires, and I have observed in darkness. When a wire is disconnected from a coil with engine running, it can jump a blue-white spark about an inch between the two. Excellent spark, I'd say, at least as far as the "juice" part goes. The timing of the zap.... that I can't feel so confident about.

    This will have to wait, though, headed out of town for a week. Thanks for all the suggestions so far, will post again when I know more. :shades:
  • pear69pear69 Member Posts: 20
    AH HA!!!!!!! Well well, if it isn't my old friend coming back to bite --yet another probing mechanic.. Oh yes -- are you ready ---are you sure----------------------------- it is a bad or corroded PCM ground!!! Your PCM fires your injectors by appling or switching the GROUND for the individual injector itself -- Make sure all of the grounds for the PCM are good and not corroded or burnt in any way. Clean them up....I'll be willing to bet that your engine runs better in the rain or in wet or high humidity conditions.

    I must warn you though, Your fuel pressure is low have it tested with a good gauge. Even 5 PSI low will cause problems -- trust me.
  • arriearrie Member Posts: 312
    You said you do not see side-arch at plugs. If you have those aluminum heat shields around the plug wire boots you will not see any side-arch if you do not remove that grounding spring from the ends of the shields.

    The spring grounds the shield to engine so that you will certainly not see the side spark and it also means that any spark leak to the shield for sure is lost to engine ground and weakens spark at the point where it should be strongest, i.e. inside the combustion chamber.

    It also is that some of the heat shields are closer to the exhaust manifold parts and side-arching can happen only on certain plugs, but to see any of them the grounding springs must be removed.

    Arrie
  • alanrsalanrs Member Posts: 25
    My how familiar THAT sounds... Indeed, the day I posted was very humid, with intermittent rain, and the day after was quite wet for my trip to the airport. The Suburban was running great. Not a hint of misfire, smooth as ever. After the eight days sitting in a lot, it was quite dry and about 70 when I drove again. Running rough as ever within 15 minutes. I just knew it was too good to last...
    So, today I disconnected the battery and pulled the PCM, checking all connections. Look good. Cleaned a couple of the chassis/engine grounds I could find. No change after re-assembly, set a 300 code. Can you point me to the location of the grounds which the PCM uses? The harness which connects to the PCM is wrapped/bundled into a big snake. The non-GM book I have is not much help with regards to the PCM or wiring.
    Will be re-testing fuel pressure. Thanks.
  • tjohnston3tjohnston3 Member Posts: 1
    I have a 03 Suburban 5.3 flex fuel that will periodically stall at idle. Sometimes it idles just fine, nice and smooth, other times, it will cut out periodically at about 1-2 second intervals. When it cuts out, the engine almost stalls, but manages to recover. Once in a while it will stall. This only happens at idle, the car runs great under load.
    I haven't been able to relate the problem to temperature (i.e. open loop vs. closed loop fuel control).

    At one point, the car was showing 3 codes, bad MAF, lean bank 1 and lean bank 2.

    I have replaced the MAF sensor, and all 4 O2 sensors, plus new plugs and wires. New PCV valve too. The codes are gone now, replacing these components smoothed out the engine a lot, but I still have this bizarre periodic stumble at idle.

    It's almost as if there is a period electrical problem that causes the computer to restart or something.

    Next step is to check for vacuum leaks on the intake side.

    Any other suggestions as to what it may be ?

    BTW, about 130K miles...
  • arriearrie Member Posts: 312
    First check that you have good connection at throttle wiring harness, i.e. remove and install harness several times to make sure you don't have a simple corroded pins problem.

    Then it could be a sticky throttle or bad throttle control motor, i.e. needs throttle body replacement.

    Sticky throttle should get helped with a good clean-up.

    Arrie
  • lakeman51lakeman51 Member Posts: 3
    Trust me on this, I fought this problem for over a year. The problem is the Intake Manifold Gasket. The original gaskets were too thin and cause this rough idle problem when the engine is cold. Mine would run fine during the summer and only had issues when the temps started getting below 40 at night. Through much research I finally tracked it down to the gasket. The replacement gaskets are much thicker and seal the air leaks. The correct replacement gasket is orange.

    Mike
  • sevenrhinossevenrhinos Member Posts: 1
    I have a 99 Chev Sub. Replaced the fuel pump 6 months ago, new fuel filter 1 month ago. Stalls out of the clear blue, and won't start for several hours, seems to be heat related but can't prove that. Could run for days with no problems but lately it seems to be getting worse. Fuel pump seems to be getting fuel to rail but don't see anything going into the carb during this start problem. I can put fuel in the carb and it starts but quits. Don't know where to turn at this point without dumping $$ into it. Was stranded next to a dealership and the mechanic simply said fuel pump. How could it be a fuel pump when it pumps fuel to the injectors? Open for suggestions.

    Brad
  • woodyjwoodyj Member Posts: 6
    Start by lookin at the fuel pump wire harness. If it looks brownish or burnt, you will need to replace the harness. Best way to check it is move the harness when the car is running.
  • arriearrie Member Posts: 312
    Simple test for fuel delivery.

    Check the fuel pressure at the fuel rail. If it reads 45 - 60 psi forget the fuel pump issue being the reason for trouble.

    If it does not read mentioned pressure range then first check or just replace the cheap fuel pressure regulator and test for fuel pressure again. If after regulator change it still does not read needed pressure then it is time to think about fuel pump failure,not before these checks.

    When car is not running the pump runs only momentarily ( 2 seconds or so) when you turn the key so you probably need someone to help with the key turning when you monitor the fuel pressure gauge.

    Arrie
  • pear69pear69 Member Posts: 20
    The fuel pump chassy wiring harness MUST be replaced every time you change the fuel pump. These connectors have a design flaw that causes them to become loose over time once they are unpluged and pluged back in. This loose connection will cause a small electrical arc (hense the burnt connector woody mentioned). It will cause your problem or worse, it can burn through and cause a fire........need I mention that a fire on the top of your gas tank is bad....
    Also, there is an infamous ground that can corrode and cause your fuel pump cut out. It is connected to the frame rail just before the gas tank. It is a black wire that breaks out of the fuel pump wireing harness just before the fuel pump itself. This ground connection should be removed and cleaned up. This is the ground that the fuel pump relies on to run. If it is corroded (and it probably is) it can cause an over load in the fuel pump circuit which will in turn cause your fuel pump to work harder and fail....This could have been the problem with the last fuel pump...
  • pear69pear69 Member Posts: 20
    BTW, you will have fuel pressure at the rail being that your engine runs sometimes. Correct the electrical issues I mentioned before you rule out a fuel pump voltage and/or issue, and then move on to the fuel pressure issues. Trouble shoot from voltage to pressure in this case...trust me, I have been there.
  • pear69pear69 Member Posts: 20
    A fuel pressure regulator for your engine is $85 bucks and is located under the upper intake manifold cover. Considering that you must remove the upper intake manifold plentum - and all the things that go along with such a job - like moving the engines wiring harness out of the way and replacing the upper intake manifold gasket - then hoping that everything goes back together properly....By the time this job is complete it will be a $300 dollar bill from a mechanic...not so cheap.
  • arriearrie Member Posts: 312
    I'm sorry if I have misled anybody with my comments. When I was talking about the fuel pressure regulator I was talking about my own '04 Tahoe. In it the fuel pressure regulator is located on side of the left fuel rail. It is readily accessible and changing it involves removing a clip. No other parts need to be removed for this job.

    I would attach a picture of my fuel pressure regulator but I don't know how.

    Arrie
  • tidestertidester Member Posts: 10,059
    I would attach a picture of my fuel pressure regulator but I don't know how.

    The help section (link at bottom of this page) gives instructions for posting pictures. You can also post them to your carspace page and link them here.

    tidester, host
    SUVs and Smart Shopper
  • arriearrie Member Posts: 312
    Below link should show a picture of my '04 Tahoe fuel pressure regulator mounted on the side of the left fuel rail. It also has a vacuum control for higher fuel pressure during fast acceleration, i.e. when throttle is opened and intake manifild pressure increases.

    image

    Arrie
  • pear69pear69 Member Posts: 20
    On a 1999 Tahoe the Fuel pressure regulator is located under the upper intake manifold. It is not readily accessible. Also, on a 99 Tahoe there is no fuel rail. These engines have (what many reffer to as) a spider assembley, which is also located under the upper intake manifold. A lot has been re-enginiered since 1999.
  • steverstever Guest Posts: 52,454
    Hmmm, the thumbnail is working ok Arrie but not the bigger pic. Please try reloading it on your album.

    image
  • navalavi8ornavalavi8or Member Posts: 5
    I haven't been following this post but I was the originator of a post regarding the same issue several years ago. My 2001 Suburban 6.0L was totalled a little over a year ago. I just want to reiterate that the issue was easily solved with some berrymans B-12 and a rag. Remove the air tube from the aircleaner to the throttle plate. Remove the throttle plate (if you want to do a good job). Hold the throttle plate open and clean the residue. There is no idle air bypass on the 6.0L and probably other GM motors in this year/body group. The idle is completly controlled eletronically and to eliminate the Idle air bypass system the machined a very small gap between the throttle plate and the housing. Once the oil/carbon residue from the egr/crank vent gums up behind the throttle plate the idle is affected. My symptoms were stalling when the throttle plate returned to idle and the computer didn't compensate quick enough. It also gets worse as the gunk builds up. Annual cleanings will illiminate all issues. I would atl least give this a try prior to overhauling your fuel system.


    Good luck
    Curtis
  • arriearrie Member Posts: 312
    Below link should show fuel pressure regulator of my '04 Tahoe

    Click Here

    Arrie
  • pear69pear69 Member Posts: 20
    Boy oh Boy, I wish the regulators on the 1999 were mounted outside like that...btw nice giant picture...
  • usmc513usmc513 Member Posts: 2
    Hi,
    I hope I'm posting this in the right area. We just bought a 2009 Suburban and have had continual stalling problems. Has anyone else experienced this or have any idea what is causing it? Thanks
  • desertsuburbandesertsuburban Member Posts: 1
    Help!!

    I have been trying to find a blog or forum where this problem can be addressed. I also have the same problem with my 2009 Suburban LTZ. I bought it in March and it has stalled/stopped about 5 times now. I'm taking it to the dealer so they can look at it. Hopefully the problem can be resolved quickly.
    Thanks,
    DS
  • kiawahkiawah Member Posts: 3,666
    Just take it to the dealership. That's what the warranty is for. Don't waste your time trying to research or fix this yourself when you have a free warranty to handle it.
  • kkrause44kkrause44 Member Posts: 2
    hey guys, I have been reading the threads and it seems like there is some knowledge here, so this is my issue. 97 chevy silverado, 5.7L (I know this is a suburban forum but the engines are the same). I have had a rough idle here for the last year ever since I had the intake manifold gasket replaced by a mechanic because it was leaking coolant into my oil. Have also had a stumble when taking off, seems like the truck misses right once i press on the gas and then drives just fine. Just lately it has started to throw P0131 codes (O2 sensor, bank 1, pre cat). I replaced the sensor, bosch, not the universal one, no change. It then threw a p0300 code and a p0305, with the blinking SES light when driving at 25-30 mph, missing pretty badly. Looked at the plug (#5), it was black and sooty, so i swapped the cyl 5 plug with the cyl 1 plug just to see if it was the plug. Sure enough, next code was a p0301! I replaced the spark plugs with the autolite platinums, after reading the posts i now know i should have done the acdelco, but its too late now. Thank you for the advice to use acdelco, i will do that will all of my vehicles from now on. By the time I changed all of the plugs, the driver side bank of plugs (1,3,5,7) were all black and sooty while the passenger side plugs were completely normal looking. With new plugs for a week, i checked them again and sure enough, driver side plugs are sooty, passenger side are normal. Still having the rough idle and random misses, usually right on takeoff. I checked the fuel pressure at the engine and it goes to 63 psi with a turn of the key, after 2 seconds when the pump shuts off the pressure immediately jumps down to 55 psi within a second, and then bleeds down to 30 psi within 3 minutes. When it is running, fuel pressure stays constant at 54 psi, but again once when shut off it bleeds off down to 30 psi. I have read that the fuel pressure needs to stay within 5 psi for 5 minutes or there is a leaky injector or a fuel pump check valve. I am on a budget here in michigan and enjoy working on it, but don't enjoy burning money on parts that don't need to be changed. I am thinking about swapping the injector pack for the mpfi upgrade, but is there any additional diagnosis i can do to pinpoint it further. Have a new fuel filter and had a dealer do their fuel injection system cleaning right after the intake manifold was changed when they also reset the timing. However since then I have played with the timing trying to get it to stop missing after the dealer adjusted it. My dad has a scan tool that gives real time readings on all of the engine vitals, (fuel trim, o2 sensor readings, etc.) is that what i would need to set the timing? Have sprayed starting fluid around intake (while engine is cold) while running, no changes in idle. Thanks for all of your time, advice, and help on reading this long post, i just wanted to give a good background.
  • dmcareaveydmcareavey Member Posts: 1
    I have a 5.3 chevy suburban and when I try and turn if over it seems to crank, but won't fire right away. Once I get it started, it runs out fine...I noticed also if I just turn the key to the run position and not start it right away and then turn it to the start position it pops right away.

    I had it in the shop getting the tires replaced and asked the mechanic and he said probably a fuel pressure regulator. he popped the cover off manifold and was trying to locate it, but after a few minutes he gave up. Does anyone know where the fuel pressure regulator would be located for a 2004 chevy suburban with a 5.3 ltr V8?
    thanks
  • kiawahkiawah Member Posts: 3,666
    check fuel pump or clogged filter, many issues w/pumps.
  • bloodynuckles9bloodynuckles9 Member Posts: 2
    Hello, my burb just started acting up on Sat. morning here in MN. very cold -30 temp. It was running rough and I was 200 miles from home. Brought to a small shop and he put on scanner and said #2,4,6,and 8 cylinders misfiring but didn't have time to go any further. I made it home but was getting less than 8 mpg instead of 16. Any ideas of what would cause this condition. Thank you.
  • kiawahkiawah Member Posts: 3,666
    That's all of the cylinders on one bank/head of the 'V'.

    I'd suspect head gasket, intake manifold gasket, or maybe something messed with the sparkplug wires on that side of the engine.
  • bloodynuckles9bloodynuckles9 Member Posts: 2
    I drove it today after being park in heated shop and still the same. A service manager at a local GM dealer said it might be the intake gasket. Another guy I know works at a Ford dealership said it would be best to put it on a GM scanner to monitor all the functions, which I gather is more than just getting error code readings. Hopefully, I'll find out more in the next couple of days. If it is the intake manifold gasket, I have read in other posts that there are different qualities of gaskets(one said the orange was is the better)? I know I am getting ahead of my self but, are there other things that should be done at the same time if that is my next step. BTW, it has 130K. Thanks.
  • markvdbmarkvdb Member Posts: 1
    One thing that hasn't been brought up on these misfire codes ( the dreaded p300 especially) is a faulty egr valve. I've had 3 different gm's and every time the rough idle was either the maf sensor or the egr valve.
  • tomlugtomlug Member Posts: 1
    I just replaced intake manifold gaskets and got the rough idle thing going on too. I pulled the connector out of the egr valve and nothing happened!. Is that a good sign that it is not working? Sounds like it to me. I'm also going to check the new wires for shorting paths also. That would be bad. The car ran well before I replaced the Intake manifold gaskets. I must have screwed something up. When you make a change and something is different, that is valid data and it should not be ignored. Lesson learned. I'll post my findings when I learn what went wrong.
  • arp10arp10 Member Posts: 1
    HI. did you ever find out what was wrong with 2009 Sub? I have 2009 Tahoe and it has stalled on me 5 different times. Once at a stop sign and the rest driving down the road. No engine lights come on. I have been able to start it back up each time. Of course I brought it to the dealership and they do not know what is wrong. Since they hooked it up to the computer and it showed nothing wrong they cannot fix it. Please let me know any info. Thanks!
  • gmcustsvcgmcustsvc Member Posts: 4,252
    Hello Arp10,
    I am from GM Customer Service. Can you please email me more information about your situation with your vehicle so I can look into it further? You can access my email by clicking on my name. Thank you,
    Mariah GM Customer Service
  • avsfreak24avsfreak24 Member Posts: 1
    I have a 95 burb with the 5.7L. It tends to bog and want to stall when I try to accelerate from a stop. If it is already moving, it usually accelerates just fine. I have replaced the ignition control module, ignition coil, oxygen sensor, and fuel filter. The plugs and wires were replaced about 30k miles ago. I figure it could be the fuel pressure regulator, fuel pump relay, or possibly the intake manifold gasket. Any advice or experience with diagnosing this issue? I do have oil on and around the intake manifold and valve covers. I know the oil could easily just be from bad valve cover gaskets and is an easy enough replacement. Could the manifold absolute pressue sensor contribute to this rough running/acceleration issue? I don't know much about MAP sensors, so I do not know how much they affect fuel/air mixture and delivery. Any insight would be much appreciated. The model I own has TBI, so it looks like the fuel pressure regulator is located within the throttle body assembly, from the way the part looks. Has anyone with an older, TBI model replaced their FPR?
  • retzmountnretzmountn Member Posts: 2
    Arp10,

    I can relate to your frustrations with your 2009 Suburban. We have a 2009 Suburban that my wife drives for her practice (Veterinarian). We purchased this vehicle in July 2009, which was an upgrade from our '03 Tahoe.

    Late last Fall my wife was driving to work on the beltway (70 mph) & the Suburban just shut down on her. No power steering or brakes. Onstar said there was nothing wrong with the vehicle. She got it started & 3 miles later, it did the same thing. We've had it into the Chevy dealership 5 times & everytime we take it in they say the computer does not show anything wrong. However, they started to investigate & supposedly found some issues. After 5 trips we were told everything was fixed & if we had any further problems GM would do a buy-back on the vehicle.

    A couple of weeks ago my wife started having problems again & it's also acting like the transmission isn't right. We contacted the dealer & they said they wanted to dig into it further (6 service visits in 10 months). Needless to say, we've been a week without our Suburban & driving a used Suburban off the dealer's lot. We ar completely frustrated & don't know where to turn at this point other than getting our Attorney involved.

    I've always been a loyal Chevy owner, but this "Lemon" has taken the cake! As much as I hate to say it, I maybe buying Ford from know on.

    Have you had any luck in getting your issues resolved?

    Thanks (Not)! :lemon:
  • gmcustsvcgmcustsvc Member Posts: 4,252
    Hello Retzmountn,
    I am from GM Customer Service. I apologize that you have had concerns with your vehicle. Can you please email me more information about your situation so I can look into it further? You can get my email by clicking on my name. Thank you,
    Mariah GM Customer Service
  • akrbugakrbug Member Posts: 1
    June 6,

    I experienced this same problem Friday afternoon. I was driving home from my children's school with 4 little girls riding in the back. When I was making the left turn into my neighborhood the vehicle seemed to suddenly turn off and the steering wheel was practically impossible to turn. Their was a vehicle approaching from the opposite direction but luckily I made it across and was halfway on the grass and halfway in the right hand turning lane to pull into the neighborhood. Needless to say I was a bit shook up. I called the dealer and had the vehicle towed, as of now they haven't found anything wrong with it.

    The only thing I can think of that I forgot to tell the service department is that I used the remote start before driving the vehicle??

    If you can help me direct the service department in finding the problem I would greatly appreciate it. I feel lucky this happened where and when it did but can't help but fear its reoccurrence.

    Sincerely,
    akrbug
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