What system tells the ecm when the motor is warm enough to kick idle down?

When I start my car cold, it idles rather high, and used to calm down quite quickly. Up to 5 minutes of driving later, it is still idling on high. It will settle down eventually, but quite a bit longer than I ever remember it being.

Even when its very warm outside, it happens. What tells the computer how much IAC is needed, and how long to do it for? Is my IAC motor dirty?

Coolant Temperature Sensor?

Is there a way to test the CTS?

IDLE is controlled by:


IAT
TPS
MAF
IAC

Your TPS voltage at idle with the ignition on should only be 0.35-0.45 if its higher the 0.45 its sort of causing the high idle. If your TPS is sticking it could also be causing it. Give your Intake tube a good cleaning, and your TB, and ur IAC valve a good clean if u havent before, lube the throttle spring and tps.

But i believe ur TPS voltage is out of range.

I have a new TPS sensor, and I have its idle position set at 0.34 V according to my laptop. I think I'll try cleaning the intake throttle body and the IAC motor... I also have a new MAF sensor too...