A4 2.0 TDi 170 Avant 56 plate Hopefully someone can help attempt to identify my problem. The story is a long one but I'll detail best I can. All of the issues have been 'addressed' by Audi main dealers. Early may, had flashing glow plugs and limp home mode. Dealer diagnosed Exhaust Gas Sensor fault and replaced. (not my local dealer as I was miles from home) Within 200 miles of this, same fault. Another dealer, diagnosed fuel contamination, oil in diesel tank. Drained tank replaced fuel pumps. Car returned to me Within 100 miles of this , same fault. Returned to dealer, believed to be hairline crack in cylinder head, replaced. Car returned to me. Within 50 miles , same fault. Returned to dealer, diagnosed contaminated fuel again, replaced fuel pumps again as well as fuel injectors. Within 160 miles , same fault. Returned to dealer, changed a fuel supply pipe (not entirely sure what) confirmed no fuel contamination. I insisted that they drive 300 miles plus and do a long journey before they returned the car to me, which they duly did. Got vehicle back, they claim find no fault. Within the 300+ that they have driven and my 80+ miles so lets say 400 miles I'm now on the M5 again have loss of power in 6th and 5th but this time no flashing glow plugs. Drop into 4th and drive at 60-70 it appears ok. lack of power and lights, junctions etc but when nailed will clear. Then won't rev over 3k rpm in idle. Switch car on off, free revving and seems ok... but I know that 80 miles down the road in a long journey I'll get the foot to the floor power loss and then have to rev the bo**ocks off it. If it happens again it's going back, would like some pointers from you guys as you might be able to help the dealer out! Has to go to a dealer as it's lease car If it helps, I don't do town driving I'm on the move big time motorways etc. Car has done 69k. Any advice as to what this can be gratefully received.