My 1982 245 GLT had a weird problem after it got warmed-up: the idle would fluctuate rapidly (from 900 to about 1200 rpm) and the car would "stumble" when I would rev the engine past 2500rpm in gear while driving. The fluxating idle would also occur immediately, even if cold, if I turned my headlights on.

I brought the car into my local autozone and they wheeled out a tester and hooked it up, had me rev to 2000 rpm, and told me my alternator was bad.

I bought a rebuilt one, installed it, and now the problems are gone. Completely vanished. My only concern is that, after about one week so far, my voltage meter on my dashboard goes right up to the red (right up to the edge but doesn't go into the red per say) and will stay there for a bit. Then it'll drop back down to about the 3/4 range on the gauge and stay there, except when I turn on my directionals, which will cause the needle to fluctuate slightly. Putting on the headlights and running the fan blower will produce a drop in the needle but won't make it fluctuate. It will drop to between 1/2 and 3/4 on the gauge when running under full electrical load (i.e. lights, blower, etc..).

Should I be concerned about how the needle goes up to the edge of the red when the car is "cold"? It almost seems like it's overcharging at first, and then backs itself off after a bit. The rebuilt alternator is the Duralast 55 amp model from autozone and it has a built-in internal voltage regulator.

I did bring the car back into autozone and had them test it again and they said it's fine and passed the test. Of course, by the time I make it to the autozone, the needle on the gauge has backed off to about the 3/4 position.

Do you think I'm okay, or should I be concerned?

Thanks a lot - RICK.

PS - The alternator belts are tightened correctly with about 1/4 inch deflection.