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), 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.

Tempted to install new Crank Sensor, then EGR valve.

Any thoughts on these?

 

Welcome to df...

you can test the egr valve with a vacuum pump to see if it's sticking. check the vacuum lines going to it and ensure there are no leaks. a bad crank sensor will not show the problem you describe.

check you coil... also I assume you have a good tuneup on it... wires good? plugs not fouled?...

 

Well it definitely fuel related. You are obviously getting spark so it's not the crank sensor.
Do you have fuel pressure if so what is it? If no fuel pressure verify the wiring to the pump. You should have 12v while cranking at the pump.
Unplug one of the injectors and plug a noid light in the socket. Don't have a noid light use a 194 bulb and straighten out the terminals and plug those in. If the bulb flickers you have an injector pulse=good!

I understand why your pouring fuel down the throttle body but that is extremely dangerous!
one lean backfire through the intake and your hand is a fireball. be very careful

Good luck

 

It could still be ignition if the coil is on it's last leg.