Thread: High Idle

I've read a few posts with similar problems but nothing that quite matches.

I have a 02 GTP slightly modded. CAI, 3.4 pulley, removed u-bend down pipe, a ZZP 1.0 PCM, Borla Exhaust.

I recently replaced the water pump and it ran for several days with no issues. The problems started 3 days ago.

Here are the symptoms.

When starting the car the idle is normal (900ish) with an ambient temp of 25-34º. As the car warms up the idle increases reaching 2,500-3,000 when the car is at running temp (185-190º)

This is what I have tried.

I checked all the vacuum lines and nothing looked broken/cracked. I unplugged the MAF started the car and let it run for a minute then plugged it back in. (saw this in a previous post which did nothing) Using Torque and a BT OSBDII adapter I could see throttle position registering .04 without pressing the peddle and gradually increase to 100 when the peddle is pressed to the floor.

Does anyone have an information on what the vacuum should be at normal idle with the Torque app?

I'm looking for some help with what to try next or look at.

Thank You.

Kurt

Maybe the IAC is bad.

I pulled the IAC and MAF out and cleaned them with the appropriate cleaners. MAF was clean as can be but the IAC had a bunch of carbon buildup. Once cleaned and re-installed the idle is running 800-850 but the physical tac (in the dash) is not showing any movement at all. It just stays at 0 from starting the car to shutting it down. I can see the rpms moving while using the torque app. What happened? lol.

The car is running without quitting, stalling or sputtering.

Oh and as a side note the Vacuum is reporting -21 to -20 on Torque while idling around 800-850 rpm's.

Thoughts?

UPDATE: The TCS light came on the last time I started the car. I disconnected the battery and reseated the PCM.
After putting everything back together all is well (for now). The tach is moving again and the TCS light is off.

Who knows..

Thanks for the earlier suggestion.

crank sensor gone bad causes the tach to quit working on and off, as well as random stalling.