maybe try testing fuel pressure at the tank outlet.
Need some hose and clamps to rig it but it will show where the problem is.

Spec is 52 psi, I think?

Blockage in fuel lines, fuel tank sock, or in fuel rail?

Tough one.

Time to monitor the output wave forms on the PEM...these are referenced ina thread here

maybe try testing fuel pressure at the tank outlet. Need some hose and clamps to rig it but it will show where the problem is. Do you mean at the Schrader valve just before the fuel filter? Or a different location? At the fuel tank outlet. Schrader valve is on the fuel rail, but you might have bloc...

Congrats for the perseverance and solving. Quite surprising about the PEM, but indeed, when chasing a problem in the dark, the junkyard is the best place, otherwise we end spending way too much.