Ok, I'm having idle problems with my 97 4.6l GT. The car likes to idle between about 500-1200rpms. I've narrowed it to only happen when the a/c is engaged. (fyi....my a/c has recently stopped working, but can't confirm that it stopped working when this idling problem started) The symptom doesn't end with just at idle, you can feel the car get throttle pulses when driving whether your foot is on or off the accelerator. I've cleaned my plenum, throttle body, and my IAC. I have just put a new TPS on it but it still runs exactly the same. I guess my next step is replacing the IAC... any input would be greatly appreciated.... THANKS!