Not much of an electrical guy. My recent struggle with a "high idle/hesitation on acceleration" cycle (along with some suggestions from brickboarders and others) leads me to believe I have an electrical problem--ECU or that damn wiring harness (it's an 87). I have a spare ECU, but I'm hesitant to put it in and possibly fry it. It seems to me (and hopefully someone with some expertise might correct me--I'm going by Haynes) that the wire that powers the IAC meets the wiring from the fuel pumps at the FP relay 87/2. Something wrong along this circuit seems as though it might account for my car's condition. Possible? I've just checked the center wire of the IAC and there no voltage w/ engine running. Shouldn't it be about 12V? My question is how might I go about isolating the problem in this circuit. Again, I don't know much about elctrical stuff. I do have access to a digital voltmeter however.