Red97LT1

Started the car this morning and it was cold (25 degrees) and almost immediately it wanted to die,until I gave it a little gas. Once I let up on the gas the idle dropped and it almost died again.I gave it gas for a few more seconds and then it was fine.


Now I am thinking it may be the IAC valve since I didn't notice the rpm going higher when cold and then dropping when the car warmed up.The rpm also seemed to drop low when I was shifting from Reverse to Drive. I'm going to check the IAC tomorrow using the diagram from shbox,but was wondering what else may cause the issue?

Injuneer

I'd start by checking the coolant temp sensor. The PCM sets the cold start idle RPM and richens the mixture for cold start based on the coolant temperature.

The IAC may also be suspect. Shoebox has a test procedure. This is a case where a scanner would help by showing you the coolant temp the PCM is seeing, and how it adjusts the IAC counts to control the RPM.

Red97LT1

Didn't think of the temp sensor, thanks. I'll use Garys software when I get home and get a log.

Red97LT1

So if it is the coolant temp sensor,I need the one up front near the water pump right? which is ?

Injuneer

The PCM reads the CTS in the water pump housing. It is a 2-wire sensor. I don't have the part numbers memorized. Shoebox has them on his website.