850 Backfiring under hard acceleration [solved]
Car hesitates badly and backfires like crazy under hard acceleration. Cant go past ~6psi at moderate throttle either, does the same thing.
Starts and idles fine.
Only happened after I replaced the fuel pressure regulator and fuel pump. Fuel pump is GMB branded and the FPR is SKP branded. Probably should have spent the extra money. So would it be the fuel pump or the FPR that's not up to the task?