My stang idles ok most of the time but occasionally it wants to die between 3rd and 4th(at about 3 or 4 pounds of boost). Also it goes crazy with the AC AND HEAT on. I replaced my IAC with one from advanced auto about 6 months ago and last time i checked it was as clean as it was when it was new. I am open to any ideas bc it has me beat. What is the likelyhood that it is a different problem? I haven't had it tuned in a long time so i dont know if its lean or what. Just thought id ask u guys before i take this on too hard.