Hi everyone, I'm hoping someone can help me I have a 92 silverado with a 350 and a TBI and I am having an idling problem. In the morning when I start the truck it idles rich and rough runs great when on the gas but idle is bad. It doesnt matter how long I drive it, can be an hour or 5 minutes but when I come to a light or a stop sign it idles real bad hasn't stalled yet just a serious idling problem.. Now here is where it gets interesting. Like before mentioned doesnt matter how long it's run as long as it begins warming up if I shut it off and start it again it runs fine. I've changed the O2 sensor, coolant temperature sensor, Iac motor wires plugs cap rotor fuel filter all the odds and ends there is no cat, started doing it last march was fine all summer then started up again now that it's cooler out.
Any suggestions would be greatly appreciated
Thank you

 

Have you checked your timing? I am having a different issue, but my idle was rough and found it advanced by more than an inch. Timing and EGR valve replacement help quite a bit.