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Chevy Suburban/Tahoe Rough Idle and Stalling
navalavi8or
Member Posts: 5
I have a 2001 Chevy Suburban 2500, 2WD w/ 6.0L engine. We purchased it from a Chevy dealership back in 2002. It was a GM buy-back, for the same reasons it's now having. NO DTC's, NO CEL.
Having a problem with stalling. It usually happens after backing out of parking areas when vehical returns to idle while shifting from reverse to drive. It then become difficult to restart. Also during this issue if vehical doesn't stall it starts exibiting erratic idle. The vehical also seems to idle low 550rpm down to 400 and lower on occasion.
I have attempted to locate the idle air valve but it doesn't seem to have one in the location in the manual (on throttle body by altinator). I can only find what I believe is the Throttle position sensor in that location.
Vehical doesn't do this all the time but nore times than not and seems to be more often during cool/cold weather.
Any help or idea would be gratly appreciated.
Curtis
See also: GM Extending Warranty On Some Vehicles For Rough V-8 Idle
Having a problem with stalling. It usually happens after backing out of parking areas when vehical returns to idle while shifting from reverse to drive. It then become difficult to restart. Also during this issue if vehical doesn't stall it starts exibiting erratic idle. The vehical also seems to idle low 550rpm down to 400 and lower on occasion.
I have attempted to locate the idle air valve but it doesn't seem to have one in the location in the manual (on throttle body by altinator). I can only find what I believe is the Throttle position sensor in that location.
Vehical doesn't do this all the time but nore times than not and seems to be more often during cool/cold weather.
Any help or idea would be gratly appreciated.
Curtis
See also: GM Extending Warranty On Some Vehicles For Rough V-8 Idle
0
Comments
The Chevy 6.0L w/ electronic throttle (no cable) does not have a idle air control motor (valve). The electronic throttle motor and pcm control the idle. On models that have no idle air control motor there is a small machined opening on on the throttle body that prevents the throttle plate from completly closing. Ater what seems to be a realativly short period of time the back side of the throttle plate and intake will have a large amount of carbon and oil from the EGR and crank vent systems. I removed and cleand the throttle body and what I could of the intake where the TB mounts and it solved all my idle issues.
BTW I will have to give the Chevy parts manager a plug because he reviewed the work orders (from 2003) and found a mistake on the paper work. The mistake was fuel injectors where replaced which actually all that was done was that the throttle body was cleaned. Then he suggested what I did to remedy the problem. I would have changed uneeded parts with out his help.
you can feel in gear stopped.i did a full tune up and changed the cat.i also replaced the fuel injectors.i think it might be a bad plug wire but at this point i give up,please help
PS
After the engine clears out the thing runs great but my gas millage is horrible.
However, I just dumped $1600 in it over a 4 week time. I replaced fuel filter, fuel pump, had my fuel injectors cleaned, 2 O2 sensors, MAF Sensor and today a throttle body. The light came on 45 minutes after leaving the service dept.
Anyone had any advice for the first one that might work with this one?
In your case, I would also make sure your battery connectors are clean of corrosion, fit snugly on the battery, and the cable isn't deteriorated at the connectors.
I assume they make some throttle body spray cleaner, like the old gumout of carb days.....
if yours dose. heres how I cured mine I first tried to replace the solenoid. That
made the car run smother but it would still stall a red lights some times. so I
called my friend who works on older cheviots.He said replace the starter and that
fixed everything I had this problem for a year and no mechanic would touch it
for under 300.00 estimate . That was a month ago and it runs better than new now.
So now, my Suburban runs fine.
Thanks,
Elorenzo39
Have any compression tests done??
Your problem sounds like a leaking intake somewhere or most likely electrical.
Keep you all posted after this weekend.
Thank you again.
You are very right. The plugs are only about 2 1/2 weeks old and I have pulled number 2 and 4 plug to compare and you are right on. The number 4 plug was black and the number 2 was perfect. I have also pulled the plug next to 4 and it was fine looking too.
Anyway, I will keep you all posted and thank you so much.
Erwin
Thanks
Hello there! I have changed out the fuel injector and unfortunately it did not make any difference. It is still running the same. If I run the car with the MAF Sensor and when the car hits 40MPH that SES light blinks. When I run the car w/out the MAF sensor the SES will not blink and run better but you can still feel the miss-fire but not as much. The only time you will feel it is when you come to a stop and on an idle. Can an O2 sensor create a misfire?
Thanks,
elorenzo39
I will help all I can, but answer the four questions I just asked. Please do not change anything on the engine. You must start from the beginning and be patient, If not then do not waste my time. I like helping people but when they go off track and change things that do not need changing then all they are doing is wasting money and time. If you did change the entire injector assembly then that is good. Even if it didn't need it, this upgrade should be done anyway..
Thanks for your help.
Spark Plug (Champion) Purchased at Autozone as well.
Wires (Dura something from Autozone
Cap and Rotors purchased at Pepboys (BWD brand)
Map/cam/crank are BWD brand
Fuel Injectors brand below. Purchased at Autozone.
Gp-Sorensen / Fuel Injector
Warranty - 1 YR 800-1513N $307.99
I changed all these part after the Suburban start running very rough. First code was a P0300. After changing and installing the plugs/wires code became P0304 and after changing the rest of the part that I bought, the code remain on P0304.
Thank you in advance for your help.
Sincerely,
elorenzo39
If the problem was not existing before the lower intake was removed to replace the gasket then lets start there..... In order to change the lower intake gasket the intake must be removed. You must unplug (and tie out of the way) the entire engine wiring harness. The harness has important ground wires that must be disconnected to remove. Follow the engine wire harness and look for ground wires disconnected. One is connected to the coolant port bolt stud (where the upper radiator hose connects to the upper intake)-if this ground is disconnected the injector ground system will overload and cause your problem. If you find all wires connected move to this---
The distributer must be removed in order to remove the lower intake manifold. Being that you had a P0300 code (a general misfire condition) the distributer gear could be worn out. Removeing the distributer to check this is not hard at all. If you changed the injector assembly then you can remove the distributer to check this.
First (most importantly) bring the no. 1 cylinder up to Top Dead Center (TDC). To do this disconnect the battery-- take the air plentum off-- remove the spark plugs and wires--locate the timing pointer on the block (looking at the engine from the front it will be just to the right of the front timing chain cover--spraying some brake cleaner on the pointer may help if it is dirty)--turn the engine "by hand" and align the timing mark on the crank balancer up with the pointer (the balancer mark is a engraved line machined into the balancer)--now very very very carefully remove the distributer cap. On the distributer cap base (where the cap screws down too) there are two notches, one has a number 8 engraved on it and one has a number 6 engraved on it (look very close--use a magnifying glass if necessary). The rotor should be pointing to the number 8. Disregard the number 6 (it is for 6 cylinder engines). This is number 1 cylinder firing position, verify this by compairing the distributer cap to the rotor position;it should be pointing to the contact for cylinder one. If not simply rotate the engine "by hand" 1 turn, until the timing mark on the balancer comes around again--360 degrees. Now you are at TDC...The following is the most important step--with a marker (Sharpie works fine) mark the base of the distributer and a point on the block ,or somwhere, to align up with when you put the distributer back in--unplug the electrical connector in the back of the distributer (cam shaft sensor)...take a break...now carefully loosen the distributer hold down bolt (13mm or 1/2 inch wrench) and remove the distributer. There will be oil dripping so be ready with a rag. Look carefully at the distributer gear. It is very common for these gears to to wear out. The replacement gear should be made of iron or hardened steel--these cost around $70. Check the price on a whole new distributer.
To reinstall the distributer it is the reverse, but make sure the base is aligned with the (Sharpie mark). Sorry you are not done with the distributer reinstall--Now you must take the truck to the dealer to get it properly timed. The ignition timing on your engine MUST BE SET WITH A SCAN TOOL. It is almost impossible to reinstall the distributer back to the exact same spot--especialy if you replace the gear. Unfortuanatly the dealer is usually the only shop that has this type of scan tool.
The timing may be the problem all along, because I am sure that after the distributer was removed by the mechanic, the engine timing was not set with a scan tool. This is a common oversight. Also if you replaced the crank shaft position sensor--and you are taking the truck to the dealer for a timing setting you mine-as-well have a crank shaft relearn proceedure done while it is there. The reason for this is too long to explain--just tell the dealer you want a the timming set and a crank shaft position sensor relearn proceedure done--it will take about an hour and will set you back around $60 bucks--A tip--before you bring the truck to the dealer make sure the engine is warmed up for at least 1/2 hour.....Also, I would get rid of the champion spark plugs and the duralast wires--why?--A/C Delco platinum plugs (not the rapid fire ones) and A/C Delco wires are the only brands that work on these engines--The ignition system voltage is very high--and for some reason A/C Delco is designed for this, trust me here. I know that A/C Delco plugs and wires are expencive but they are the only brand that works and they will last another 100000 miles..I would bite the bullet and put in new plugs and wires--see what happens...Keep me posted...
Thanks,
elorenzo39
P.S. sorry I couldn't reply last night, the site was down.
Thanks again and have a great weekend.
Thanks for all the help and advises that you have given me.
Elorenzo39
I wish I could tell more about the Distributor Assembly. I did not see it myself. Dealer just called me and asking me for approval to replace it and I approved the work over the phone. They are jam pack with a few Suburbans and Silverado's with the same issues. They actually had my Truck for a few days. Dropped it off Last Friday and did not get it back until Wednesday morning. Service advisor told me that they are working on alot of vehicle that has the same problem as mine.
Thanks again for all your help.
Elorenzo39