Stalling At Idle

[UpAndDown]

I have an 08 Tahoe LT 4x4 with the 5.3 in it and around 135k on it. I only drive it primarily on the weekends because I have a work vehicle. A few weeks ago while at an extended idle and in park the engine died. I turned the key off and on and it started right back up immediately with no CEL. Last weekend I got gas and started the truck up afterwards and was scratching lottery tickets and it happened again twice. Again, it starts right back up immediately and has no check engine light. Before this truck I had a 05 TrailBlazer with the 4.2 straight 6 and had this issue from time to time and the fix was to clean the throttle body. It would get caked on pretty thick on the back side of the butterfly. Is this a common issue in these as well? The symptoms are identical. If so, is there anything to know before cleaning? I used to take the throttle body off and clean it and manually operate the flap and reinstall with no issues as far as relearning idle or anything else. Can this be done the sane way? If not, what is the procedure? Thanks in advance for all replies.

 

[Doubeleive]

I have an 08 Tahoe LT 4x4 with the 5.3 in it and around 135k on it. I only drive it primarily on the weekends because I have a work vehicle. A few weeks ago while at an extended idle and in park the engine died. I turned the key off and on and it started right back up immediately with no CEL. Last weekend I got gas and started the truck up afterwards and was scratching lottery tickets and it happened again twice. Again, it starts right back up immediately and has no check engine light. Before this truck I had a 05 TrailBlazer with the 4.2 straight 6 and had this issue from time to time and the fix was to clean the throttle body. It would get caked on pretty thick on the back side of the butterfly. Is this a common issue in these as well? The symptoms are identical. If so, is there anything to know before cleaning? I used to take the throttle body off and clean it and manually operate the flap and reinstall with no issues as far as relearning idle or anything else. Can this be done the sane way? If not, what is the procedure? Thanks in advance for all replies.

no need to remove the throttle body unless you have not kept up on it and it is extremely dirty, otherwise you can clean it installed, also replace the air filter and clean the maf, be sure all the housings are put back on nice and tight so there is no air leak
if the problem persist's then it could be time for general maintenance, injector cleaning, new plugs/wires
you might also want to monitor the fuel pressure with a fuel pressure gauge, if the pressure is dropping it will not give any code unless it becomes severe and causes something else to trip. 43+psi is normal (engine running), key-on engine off is 50+, if it is a hybrid the ranges are different.
another possibility although pretty rare is crappy gas

 

[UpAndDown]

Thank you for the reply. I’m not the original owner. I bought it with around 115-120k on it from what I remember so I’m not sure of prior maintenance. As far as cleaning it from the outside, can I manipulate the butterfly without causing any issues with the idle after I’m done? I know this wasn’t an issue on the 4.2 but I’ve heard of certain engines that need some type of relearn with a high end tool if the throttle body is played with. I know that on my TrailBlazer all of the buildup was on the inside of the flap so I would be able to clean it without opening the butterfly or removing the whole throttle body. Good advise about the MAF too thank you and I recently replaced the air cleaner. Thanks again for the help and all replies are appreciated.

 

[UpAndDown]

Anyone have any answers to my last questions? All help is appreciated. Thanks

 

[Fless]

To be safe I'd remove it to clean it. No better way to get behind the butterfly.

 

[UpAndDown]

Thanks Fless. Is there any risk in doing it that way like needing some kind of an idle relearn from a high end scan tool? Is it ok to manipulate the butterfly while it’s off the truck or will a motor or solenoid or something in there get damaged? Thanks again for the help

 

[Foggy]

Thanks Fless. Is there any risk in doing it that way like needing some kind of an idle relearn from a high end scan tool? Is it ok to manipulate the butterfly while it’s off the truck or will a motor or solenoid or something in there get damaged? Thanks again for the help

You'll be fine. Use Throttle Body Cleaner...not just old carb cleaner.
Make sure to pick up a new Seal as well... It's a round seal that goes into the
crevice on the intake manifold. And just hand tighten carefully the Throttle Body
bolts and nuts (2 studs, 2 bolts) by hand til they just bottom out - carefully