Hi I am having trouble figuering out whats wrong with my car. Idk if my alternator needs to be replaced or just cleaned. I just bought a used battery from advance dicount on sunday. The guy there hooked up a volt meter to my new battery and it was 12 volts when runnin and then alternator and it was putting out around 11 and 12 volts when it was idleing. He said that my alt was fine but al lil low so I should take out the alt and take it apart and clean the inside components because my car is so old that crap could be stopping something from makig a good connection. It was running just fine until today when my car had to be jumped after I stopped to get gas. Then when I was driving home tonight my volt meter in my car was reading about 9 or so even when I was accelerating it was only about 10. My dash and head lights where really dim when I stopped at a red light and my vm dropped allthe way down to below 8. Then about 10 min after that my car seemed to be workin just fine cause when I stopped my it stayed aroun 11 or so and when I was goin 60 it went up to around 12. So if you can help me I would really appreciate it.