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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.
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
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.
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.
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
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----
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.
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:
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.
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
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.
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...
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
Mike
Brad
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
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...
I would attach a picture of my fuel pressure regulator but I don't know how.
Arrie
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
Arrie
Good luck
Curtis
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Arrie
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
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
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
I'd suspect head gasket, intake manifold gasket, or maybe something messed with the sparkplug wires on that side of the engine.
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
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:
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
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