Im new here, hoping I might be able to get a little advice. Heres my story. I have a B6 A4, with 98,900 miles. About 5 months ago, check engine light came on. Several fault codes including running lean, misfires etc etc. After replacing 4 check valves, all plugs, all coil packs, found severe internal vaccuum leak, replaced O2 sensor, blah blah blah...the misfiring stopped after leak was repaired but lean code still wont go away. The started hearing whining in the rear....now replacing fuel filter (hope its not the pump). On top of that...the dng misfires came back again. Car jumps, idles low, when stopping and it shifts into 1st it revs itself up to about 2rpm AFTER its already stopped. (retarded). Sooo...Im hoping replacing fuel filter will solve the lean and whining issue....but the misfires??! I mean come on! How many vaccuum leaks can this friggin thing have? I've tried to find issue using carb cleaner...no luck. Everytime I've repalced a valve, its fine for awhile, then acts back up again. Im about to put some c4 in the engine, drive it out to the desert and have my own 4th of July show. Any advice on whats causing all of these leaks or what else it could be now?