2005 Vulcan FFV will not return to normal idle speed when AC is on -- 2500+ RPMs and is difficult to stop at traffic lights or stop signs. No Codes! As soon as the AC is switched off, engine returns to a normal smooth idle and I never see the problem at all if the AC is not turned on. I was able to research this problem on the internet and I found a similar problem for a Taurus with a Duratec engine. That fault was caused by low alternator output when the AC was on, but my alternator is outputting a constant 14+ volts, even with the AC on. I have changed the IAC which has had no effect on the problem. I suspect the PCM but I am reluctant to spend that kind of money without confirmation of my diagnosis. I am also reluctant to take it to a dealer for diagnosis because I am afraid of what that bill might come to. Does anybody have any insight into this problem?