I read a number of threads but nothing sounded exactly like what I am dealing with. A couple times a week I will jump in my truck in the morning and drive to work and it starts just fine and in the afternoon when I start it, it starts just fine but will not idle and quit. I turn the key again and it will start but will not idle. I then turn the key with my foot on the gas and I have one foot on the gas and one on the brakes. I drive for 15 minutes and then everything is fine.... I had the 100K tune-up 6-7 months ago. I don't want to take it into the shop and pay for a diagnostic and have them tell me they don't know what is going on... any help would be much appreciated.

 

Idle Air Control Valve. Take the throttle body off the manifold and then take the IAC valve off and lookat the pintle tip. It will probably have some grime on it. Try to move the pintle in and out very gently to make sure it is not siezed. It may just need cleaning on the tip. Here is a video of how too...

 

Thank you ruffneck. I will see if I can get to that this weekend.

 

Welcome!! Let us know the results.

 

Also try cleaning the butterfly at teh opening of your throttle body. Your senario sounds just like what my grandmother's 01 Chevy silverado did, but with a 5.3. I cleaned all the gunk off the biutterfly and blew throttle body cleaner all in the throttle body let it soak for a bit and cranked her up... No problems now.

 

Thanks wolf. That sounds easy and I might try that first.

 

I am experiencing the same problem with my 2000 GMC Sierra Z71 (5.3 ltr) as described in Jbens' posting. The same procedure was used as described with holding the brake with one foot and the accelerator with the other foot to hold the engine at idle speed (about 500 rpm). While on a trip out of town, I took the truck to a dealership. First trip: cleaned throttle body and installed new air filter ($138.58). Next day same problem: took to dealership -- they replaced the Idle Air Control Motor (probably the same as Idle Speed Control) at a cost of $235.93. After returning to my home city, the truck stayed parked for 3 days. Yesterday when I started the truck, it has the same problem.

 

Are you sure they cleaned the butterfly at teh opening of the throttle body? Remove your air ducting and look to be sure there is no black gunk caked up around the edge and the small circular opening of the butterfly. If it is indeed clean then look for play in the butterfly rod that holds it. I read somewhere that teh rod or bearings/ bushing develope slack/ slop and can cause the same problem. I will try to find that thread...

 

I can not find the thread I was looking for, but maybe someone will recall it and point you in the right direction as to what I am talking about when it comes to the throttle body rod that holds the butterfly.