lol well turning on the ac always had an effect on the rpms at idle, but not this drastically so i think i know what you mean... and this gives me one more thing to check, thanks guys.Turn it on and observe for changes in RPM.
x2 in the IAC disconnection. I've been seeing a lot of taco IAC's dying lately for some reason, check the resistance of the coils in the IAC valve.Dam Mike always something, Have you disconnected the IAC when running and observe RPM?
Check AC like stated above as well.
Do you have a CEL??