OK so as soon as you fix one problem another comes along. At high revs the car backfired once on the LHS looses power and finally the engine cuts out and wont restart. Leave it for a day and it restarts and runs OK then the same thing happens again. Runs fine at low revs. Thinking it must be the PTU although I have not long changed it for a Series 2. The PTU was secondhand. UK car Twin Turbo. Any help most appreciated.