Here is the strange problem that has plagued my car for a while now. I have replaced the IACV and TPS and it didn't fix it. EDIT: I believe I found the problem. One of the bolts holding the EGR to the UIM was broken off, and was allowing a vacuum leak around the EGR where it wasn't sealed down tight. I've got a new UIM coming, and will update if that fixes my problem!
1999, 2000, 2001, 2002, Mercury, Ford, Cougar, Duratec, 2.5, 2.5L, V6, uncontrolled, acceleration, rev, hang, throttle