When I rebuilt my altenator in the mystique I had to turn down the slip rings on a lathe. They were completly out of round. It seems a lot of 99s have altenator problems. There was probably a bad batch and they show up after 50 or so thousand miles 70k in my car. When the rpms get up high the brushes aren't capable of staying on the rings causing the dimming lights and battery light. This is just my guess but since turning the rings, replacing the brushs and regulator I haven't had a problem in 10k miles.
