Recently had my 2003 A6 3.0 in the shop for P1998 & P1196 codes both to do with cam friction too high. Mechanic said most likely sludge build up and very expensive to repair. I have tried two treatments (1/2 of recommended amount) of Seafoam in the crankcase only with oil / filter changes within 30 miles of each treatment. I was afraid it might 'knock' too much crap loose too fast. It has seemed to help, CEL stayed off for over a week but now it comes and goes. Question is will Seafoam or some other induction cleaning treatment help finish off the sludge / carbon buildup that could be causing the cam friction problem ? Thanks for your assistance !