

Using an improper wheel is most likely to blame for metal particles lodging in abrasive grains or in wheel pores. Try using a wheel with a coarser grit or more open structure to provide chip clearance. Also try using more coolant. Faulty dressing could be another cause of wheel loading....
Oil may leak from the rear crankshaft seal after seal replacement due to the seal lip rolling while installing the new seal. This condition affects 1996 A4 with 2.8L V6 (Engine Code AFC). When replacing the seal, the new seal is supplied pre-installed in the flange.
Hall effect crankshaft position (CKP) and camshaft position (CMP) sensors are critical components of an engine management system. The inputs they provide enable the powertrain control module (PCM) to determine engine speed and position including where a given cylinder is within the four-stroke cycle.
Thanks to the increasing reliability of modern vehicles, most diagnostic technicians are seeing fewer pattern-failure driveability complaints. For that reason, many techs won't gamble expensive shop time chasing an illusive no-code driveability complaint. Instead, many will write "no problem found" on the repair order and move on to the next...