Okay, I just got a 85 camaro with a 2.8. When I first start the car it shows low voltage on the gauge and an erratic idle, sometimes even dies. After it has warmed up it shows normal voltage and idles smooth. Now, after it has warmed up and I turn on the lights the voltage drops off the scale as far down as the needle can drop, one signal light sticks on, the tach pegs out, but the idle doesn't change. Could the alternator cause all this? The guy I bought the car from said he was having alternator probs but people don't always know what they're talking about. Gonna get a voltmeter this weekend and do some more tests. Anyone got any ideas?

 

Bad batt?
That volto' meter will answer your question probably lol