Ok im new here got a vette figured i need to get sighned up. so heres the deal my 90 vette has a pro charger supercharger tune port 350 all kinds of aftermarket stuff the motor is built pretty stout. the harness and computer are all oem minus intake and injectors wich are aftermarket. the car runs good but blows black smoke and has a sparatic lopy idle it also backfires from the intake sometimes at quarter throtttle or when you stomp on it. its obviously running way to rich. ive changed out the temp sensor, tps, map, checked for boost leaks checked the timing, wires, plugs, disributor. no ses codes come up. it has an aftermarket fuel pressure regulator diaphram style could that be the problem? im stumped on this one any suggestions would help thanks