The car runs fine currently. But when I turn on the headlights, ALL the guages go dim, And the car starts to vibrate excessively as it drops in revs 400's and climbs back up to 500. All lights go dim when I use any thing that uses power at idle. The headlights actually go dim when I roll my windows up and down. Seems like the alternator is not generating enough juice to keep her running. Perhaps its my battery also? I cant remember when It was when I changed it. I have stock speakers and regular old cd player. Please help me diagnose this problem. Thanks

 

I would stop by a place like autozone and have them test the battery/alternator. It could be either one causing the problem.