i JUST DONATED-MY QUESTION IS A FOLLOW UP OF PREVIOUS QUESTION-95 CHEVY G20 VAN 350K TBI,VAN WILL ONLY START IF ACCELERATOR TO FLOOR, BLACK SMOKE FROM TAILPIPE, NO POWER,DIES IF ATTEMPT TO DRIVE. I HAVE REPLACED PLUGS(BLACK FROM TOO MUCH FUEL) WIRES,FUEL PRESSURE REGULATOR,CAP & ROTOR.I CAN HEAR FUEL PUMP BUILD UP PRESSURE WHEN KEY IS TURNED ON(INJECTORS NOT LEAKING), NO CHECK ENGINE LIGHT ON,NO FUSES BAD,NO AIR INTAKE RESTRICTION. CAN I UNHOOK EXHAUST FROM EXHAUST MANIFOLD TO CHECK CAT CONVERTOR OR IS THERE SOME CHOKE MECHANISM ON TBI THATS STICKING OR SENSOR THATS CAUSING EXCESS FUEL TO ENGINE. I CAN'T DRIVE VAN TO GET SOMEWHERE TO DO DIAGNOSTICS BECAUSE IT DIES WHEN ATTEMPTING TO DRIVE.THANKS IN ADVANCE-SK