Have to keep Pumping the Pedal

I have read & read but I've found nothing..
94 Ford E350 460 engine Fuel Injected.
Things replaced...
1. Fuel Pump/Strainer/Filter
2. Fuel Pressure Regulator
3. TPS (Throttle Position Sensor)
Sympton...
1. Will not run.
2. Will crank and has spark.
3. Can get it to start when I energize a fuel injector with 12v to the red wire and touch the ground to the fuel rail with a momentary connection. This causes the fuel inj to tick and the fuel pump to prime up.
4. Hit the key and play with the gas pedal and it runs. The deeper I push the pedal the faster it will run,(as long as I'm pumping it).

Any ideas??? I'm trying to help my elderly neighbor get this running and I'm out of ideas..

Thank you in advance for any and all help.

Update:
I have been told its a possible computer problem or ignition switch. Anyone else had this happen?? If so, what was the outcome?