car has no power on 1990 Volvo 780

after reparing warped head, test drive at70miles hr. backfired after slowing to return home. checked timming,cylinder pressure,replaced master flow sensor. car starts but no power!HEIP!

Asked by for the 1990 Volvo 780
1 answer
Do you have a way to check fuel pressure? Does it have an EGR?
Do you have a diagram with the relay layout?