1992 RS automatic 5.0 l, stock motor but aftermarket alarm, was idling oddly, low when waiting at a stop light, etc, and getting progressively worse. Some work was done by someone less than a professional which included changing out the starter and the fuel injectors (don't ask). Fast forward a while and a professional worked on it, fixing what the other person did and replacing the alternator, twice.

From what I understand, when the alternator is disconnected, the car runs wonderfully, it just does not charge and the oil pressure gauge jumps around randomly. When the alternator is connected, it pulls too much from the motor and causes it to stall as the idle is all over the place. It was because of this issue that the mechanic changed the alternator twice, first thinking it was just a bad replacement alternator. After spending about 30 hours of looking for some cause, the mechanic gave up and sent the car home.

The car has even had a visit to a dealership which suggested one of the fuel injectors was bad. They'd be happy to fix that for $700 then get into the electrical/idle issue. No, thank you. (If it runs well without the alternator then how can a fuel injector be bad?)

Short of paying an electrical specialist by the hour for a week's worth of wages to try to diagnose the root issue, is there some workaround that might be possible, like with an external battery charger maybe, or any other ideas? It's not a daily driver but used maybe twice a week.

 

 

Thanks much for the insight! I'll have that configuration double checked!