hi there im not sure if it is the inertia switch as it was running lovely before the bang, i had it running,took it for a short run it jerked a couple of times,but when i got it home it died.it doesnt even sound as though it wants to fire and there is no fuel going to the engine and i cant even hear the pump working and there is no spark at the coil pack even though i have put a brand new one on.i will try the inertia switch as well thanks for the advice.

You need a diagnostic code read. This could be a crank or cam sensor failure. Regards Peter