Thread: High idle after getting off the freeway.

I took my GTP out yesterday after 20-25 miles on the freeway. When I got off and was sitting at the red light the car was idling really high 1500-1800rpms. When I left off the brake pedal the car would accelerate very quickly all on it's own. After turning the car off and starting it back up everything was fine.

I had my OBDII scanner with me and everything looked normal. Anyone have any ideas?

I have already checked for vacuum leaks and found none. I was thinking TPS, but I had a 0.0% reading when it was idling high, but when I put my foot on the pedal the % increased like it should have.

Clean IAC that's about the only thing beyond the throttle plate that could do it.

My IAC is new. I replaced it earlier this year . It still might need a cleaning.

Make sure the IAC is the correct one. My north star TB had a incorrect IAC installed and kinda worked correctly for a few months until it suddenly fell to pieces inside its housing in the TB.

I will check that. When I ordered it I got one for a l67 specifically but who knows if that is what I got.

New does not mean infallable. You have an issue and if your pcm doesn't see throttle or you aren't getting a bunch of extra air..you can't increase rpm.

Sorry if your new part doesn't like my idea on your issue.

It wouldn't be the first time I had a new part go bad. I got several other IACs I can try. I will swap one in for the next time I get it going down the freeway and see what the results are.

Thanks for the help guys. At least I know where to start.

Throttle cable wouldn't be sticking would it? I've had that problem before in my dads 01

Sent from my Galaxy Tab 3 8.0

Nope I dont think so. I tried to pull up on the pedal but that did nothing.