turbos been done by vince at cr turbos,then sent back 2b checkd. had full re-build,new 0.5 oversize pistons,rings,bronze guides and ford stem seals. im very surprised nobody knows the problem (including myself) im led to believe that the 4x4`s do smoke on over-run because the ecu`s designed to spray fuel in2 pistons to cool them down on over-run.but i think my cars a bit worse than that...