I have vw transporter 2.0 petrol with electronic ignition,pulled up at destination van stalled restarted ran for 3 or4 secqnds backfired then would not start,checked cambelt timing and belt ok,no spark at plugs,no spark on coil ht lead,checked power to ecu 12v at black wire, other wires all live except earth,cranked engine with tester on all wires remained the same no fluctuation on any wires,seems to point at ecu, any help appreciated