Iowa Chapter Director
Join Date: Jul 2002
Location: Ames, Iowa
there are only 3 things that can cause this, all involving air to pass by the throttle body.
1. Your throttle body's adjustment screw is open too much (not likely because that would only happen by twisting it yourself)
2. Idle Air Control valve is bad. (also not likely since you just replaced it)
3. Vacuum leak.
1988 Notch Mustang: - 438W, direct port n2o, t56
2003 SVT Focus: - SCT X3 tuner