99 tahoe turns over but does not start

The wiring harness was changed by the original owner. I poured gas in the intake and it started so i bought it thinking it was only something minor. So far i have changed the fuel pump,filter,crank sensor,cam sensor,had the computer flashed. Fuel pressure is 60 psi and im getting fuel and power to top of motor. It runs great when i steady pour fuel in intake. Any help would be greatly appreciated.