I've searched to forum but didnt see anything that resembled my problem. I've got a 93 5.0 with no mods. I parked it a few years ago because of numerous problems including a bad idle at startup. It starts fine but the idle will fluctuate up and down and the car will die if you dont give it gas. I hear the throttle body opening and closing when its doing this, sort of like a dying horse gasping for air... It does this until it get really warmed up. I also believe the alternator is going out because when I turn on the lights, fans, wipers and any other accessory at the same time the battery voltage drops way down. Even at idle once it warms up the voltage is not showing correctly. Could the alternator be causing my idle problems? I plan on checking the IAC motor when I get home to see if its dirty.

 

Cleaned IAC and she purrs like a kitten. Still un sure about the alternator but I will be getting that checked out at Advanced today.

 

Just put a volt meter onthe batt. while the car is running... a charging system will read around 13.5 to 14.5