I have a 91 GMC Sierra 350 1500. It turns on fine but will not stay on unless you keep your foot on the gas pedal. I have already changed the spark plug wires, distributor,rotor, air filter, fuel filter.......I have no clue what could be causing this! I also checked the fuel pump and it is working fine. I tried resetting the computer by disconnecting the battery for a while but that didn't help either. Please help!

Have you ever replaced the TBI gasket? They are notorious for going bad causing a major vacuum leak. Check for any broken or cracked vacuum lines. Also make sure the PCV is working. It should rattle when you shake it.

After you check/fix the TBI gasket. Take off the air cleaner and make sure fuel is coming out of both injectors.

//2000CAYukon