2001 trans am engine misfire
random misfire popping thru exhaust 1and 3 plug fould like a vacuum leak but the misfire is all over the board it has new plugs and wires and 3 new coils before it was brought to me
Well.. If you haven't figured it out by now, I would say go with your hunch.. GM uses vacuum controlled fuel pressure regulators. With the misfires and fouled plugs, I would look for a vacuum leak.
Bad valve train Brook spring Bad cam