1996 Trooper 5 Speed 3.2 SOHC

At idle the output is great but as throttle and/or load are applied the output drops to 12v or a bit less. When you let out of the throttle to coast the voltage comes back.

It manages to keep the battery charged and has never stranded me but I am worried about it. My 1995 Automatic has enver done anything like this.

I'm going to take it in to an alternator shop but wondered if others had seen this behavior.

Mark