what can i use to remove the black exhaust from around my exhaust tips on the plastic bumper, the car is running rich?? thanks.

 

Clay bar..

 

clay bar??

 

Oh, ok I assume you have not heard of detailing clay bars, they remove surface contamination. Just do a search on this forum, every one makes one now, Mothers, Zaino, Meguairs...etc.. You ought to clay your entire car you will be shocked how much crap will come off the paint.... Just fee of the top of your back bumper, I bet it is rough as all get out as all F bodies get with the build up of brake dust and carbon on that area.........