This really only happens after cruising at a higher rpm/mph on the highway and then end up sitting in traffic, and at stop lights. But I will be stopped at a light and will notice the rpms consistently rise slightly and even make the car want to move forward a little...but just pushing on the brake a little harder keeps the car from moving.

I would have to think this has got to be some kind of sensor that is dirty or so. It doesn't happen all the time, but it happens enough. Doesnt seem to happen unless I did drive it on the highway, and then get off into stop and go traffic however. The Idle Air sensor could be dirty maybe?

Anyone have some input on this? My car is speed density, so no MAF.

Cory

 

Try cleaning your IAC first, cheap enough to check

 

Thanks Javy! Good to hear from a local. The IAC is on top of my throttle body? Would some carburator cleaner or something work well?

 

I haven't experienced this problem with my Camaro, but I have had this identical sounding problem with my 90 454SS truck. The problem began to appear after a performance rebuild of the engine. It generally exhibits the problem in higher ambient temperatures for some reason. I never have a problem with the rising idle during, say a redlight stop in the winter months. I haven't been successful in eliminating it, but reduced it. I did get very familar with many sources that could cause such a problem. Yes, the IAC is number one on the list.