Pontiac Problems? Ask a Mechanic for Answers ASAP
You will need to do some testing. Do you have a battery charger/tester? or a volt/ohm meter? or the hand tools to remove the alternator and have them tested at a local parts store?
Okay. Some measurements and get back to me. Measure the voltage between the positive and negative terminal of the battery, the big terminal on the alternator and the battery positive. Also measure between the big terminal on the alternator and the battery negative. Record those numbers and get back to me.
Also, so I can be sure we're not wasting each others times what exactly is it that your car is doing?