A couple of things I can think of, Check for primary voltage at coil with key off, engine running. Shouldn't be any primary voltage with key off, if so, my first thought is the ignition switch.
It could be dieseling, ignites off high cylinder compression, no spark, or a hot spot in the cylinder/s?
I haven't looked at your wiring yet, but, if there is an oil pressure switch wired in parallel with the fuel pump relay. As long as you have oil pressure, the pump can run, even if you unplug the relay.
Tuesday, June 23rd, 2020 AT 5:29 PM