new2chevy

Hey guys,

My 95 Firebird idles at 2,000 rpms in the morning lately. It doesn't have to be too cold for it to happen, either.

Even if I stab the throttle over and over again, it still idles at 2,000 rpms. Once I get on the road and drive the car, the idle will drop down to normal, when I come to a stop.

I'm not sure if it is colder weather related or a sensor on the engine somewhere or what it is.

Any suggestions?

Thanks!

parkers Z28

Have you scanned for codes ? There is a sensor that controls your idle at cold starts I think its on the water pump?
I'm sure shoebox has something about it in his location views!!! #5 & #9
#9 engine coolant temperature for pcm ... has something to do with cold starts??

Injuneer

The PCM elevates the idle RPM at cold starts, based on the coolant temp sensor reading (in the water pump housing). But the max RPM programmed in is 1,200 RPM for sub-0 temps. Doesn't explain 2,000 RPM.

I'd start by checking for sticking throttle blades or linkage due to the cold. If not that, start looking at the IAC motor. If you had scan software, you could look at how the PCM responds to the elevated idle RPM. It may be commanding the IAC closed, but the IAC may not be responding.