I got in my car last night and turned on the lights. when i did the dash lights were out then they came back on. after this happened it was warming up and the temp gauge dropped off suddenly then started bouncing with the rpms. i got in it today and the gauge started going up then dropped off again. i dont want to run it without knowing if im cookin it. maybe a bad ground?

 

Bad battery cables or ground, or a failing alternator.

 

I found a broken wire. Someone hacked one in that came loose. All good now.