My 92 regal 3.8 is sort of randomly giving low voltage when idle or even cruising. Its going well below 13V on the dash and headlights are dimming, and check engine light comes on.

When im accelerating, the voltage gauge goes up, always, and check engine light is gone. It goes back down several seconds later if I just hold my speed. Sometimes it keeps giving a good reading when idle/cruise but eventually drops down, and CEL comes back/lights dim when it drops. I am hearing a click from the dash i believe, when this happens.

I put in a new alternator early this year (same problem) and everything seemed good for several months, then one day I needed a boost and once started, it was getting low voltage on the dash and it soon stalled. I figured the alternator was pretty new so I had my battery replaced. It started up and gave good voltage at idle but days later it was dropping and almost only going up when accelerating.

Also, and this might sound funny - It seems to be effected by bumps on the road, a quick volt drop and CEL flicker if I hit a sewer or something.

Im not familiar with using testers, so Im just looking at the dash gauge for everything Ive said. I did not notice any sounds or smells from the alternator though.

thanks in advance for suggestions