I have a 2016 590i with 200 hours. Engine starts just fine. As soon as pedal is depressed it starts missing and backfiring through intake. It will not move. Back off the pedal and it idles fine. Fuel pump runs for short time when key is turned on and shuts off. Once engine is running I can't tell when or if the pump restarts. Have changed fuel filter and swapped the relays, same effect. Looking for suggestions.