My son drives a 1992 Chevrolet Lumina Z34. When you start the car first thing in the morning it idles very high (often bouncing off of the Rev limiter). Once the car warms up it runs fine. The two codes that set on the car are for the IAC and EGR valve. I took the EGR valve off of the car, cleaned it, put it back together, and tested it. It appeared to work fine (pretty simple, 12V input and the computer supplies the ground to actaute the solenoids). The car ran the same once the valve was re-installed so it doesn't appear to be related to the idle problem.

Has anyone experienced this problem?It only runs rough (much higher RPM than normal) when it is first started in the morning. I appreciate any help/guidance you can provide; I am afraid continued starts like this will damage the engine/transmission (he doesn't always wait until it is warmed up, so he often shifts it into gear at very high RPM).

Thanks!![/align]

 

Did you check the IAC? I could be wrong but I belive that is part of the system that speeds up the engine when it is cold. If it is bad it could race it.