94 5.2L will only start and stay runningif we trickle gas down TB; will idel smoothmomentarily, then runs lean and idles rough then quits.

Relays and fuses all check out ok, Replaced the Fuel pump with new one (twice because we suspected that the first one was bad..out of the box), Installed new TPS, removed and cleaned TB, IAC valve, injectors and fuel rails (rails were shiny clean), also blew out fuel line front to back (scavanged fuel and found NO debris) lines were totally clean. Original problem still exists. Installed new EGR valve, Crank Sensor, Oxygen Sensor, Dist. Cap, Rotor, Plugs, Wires, Coil, Bought a used brainbox...no change....Hollowed out the converter...same problem! Checked the wiring harness...12 volts at the pump for prime and while cranking.

I haven't bought a fuel pressure gage yet...but it seems like I'm not getting very much fuel pressure when I push the test needle in on the fuel rail.

Any suggestions?

 

did you check the fuel line to the tank?

 

Sorry re-read your post and seems like you would have found a leak in the fuel line when you blew them clean from front to back.
Good luck

 

what's the fuel pressure? is the regulator on the rail or on the pump?