Dan,
When you changed your fuel pump, did the new pump kit come with a new pigtail connector for the wiring harness side? I have a 1998 tahoe and many years ago the fuel pump connector went bad intermittently. Sometimes the truck would not start. Wait some time and it would start. I finally narrowed it down to the connector and changed it out. Problem solved. A few years later I changed the fuel pump and the new kit came with a new connector and heat shrink but splices. No intermittent starting problems since. Except when the passlock system acts up. But like others have said, the truck will run for a second then just die. Good luck and keep us posted.