i just spent 4 hrs tryin to diagnose a sc400
when the car hit 6 kmh it would shut down
when running car in air it was ok
traced it back and eventually found efi relay was turnin off for split second
which made engine stall instanly
i tightened terminals and put an extra earth on the relay earths incase it was a bad earth
but they have a shitload of wiring and ecus and its not hard to get stupid nigly problems
