Misfire at 5500 rpm and 250 kpa in G4+ Posted June 12, 2018 · Report reply I checked timing sync with a timing light and it's spot on. Fuel pressure is correctly rising 1 to 1, there is a Hobbs switch to activate the second fuel pump, and I have tried less fuel as well as more without any change to misfire with fueling changes verified on wideband. Is the Pull-Up resistor for DI1 on the board or in the software? I spoke to the customer and this issue was present with the previous motor as well as with the stock ECM. The injectors were tested and flowed, new wiring harness, proper grounds direct from battery to block as well as chassis, tried several ignition systems, new fuel pump and fuel lines. Only the crank and cam sensors remain the same, but I would assume it would show up in the log. Voltage is good as well.