Plot hole: Although Marty rips the fuel line, not all the fuel would have drained out of the tank. Only the fuel that was already in the fuel line would have leaked out, meaning it could simply be patched, bled and the engine would run without a problem.
Suggested correction: A cut fuel line could absolutely drain the tank. Even if not a direct route with respect to gravity, it could still create a siphon effect and drain the tank.
Plot hole: During the final fight, electricity plays a strange, inconsistent role. Leaving aside the cheesiness of the blue sparks effect, it's quite odd that when said sparks signifying electricity travel up the cable, they do it just up to a certain height at first, but all the way up when it's time to kill the villain - in fact they should have travelled all the way to begin with. Not to mention the fact that Gibson has been touching the metal pretty much all the time and not just when he bodyhooks himself to it with the villain. (01:43:20)
