Wondering if anyone can help . My a4 quattro 2.0 tdi 57 plate sets off like a rocket . Drives superb at sensible speeds . When i really boot it it starts to pick up then feels to slip for a second then goes again . Ive tried the usual clutch tests . Starting up hill in second , driving at 25 and going straight to 6th from second and it passes every one its just at high performance. Help please .