Truck Repair: 1990 f450 460 engine, fuel leaks, throttle linkage

Question
truck wont stay running...will run for a little while as lon as i keep pumpinf gas pedal. soon as i stop it stalls out.. i changed the fuel filter and it is getting fuel to injectors

Answer
There could be a couple of reasons for this:
1. Check the throttle linkage if it is mechanical control, adjust as necessary to obtain slow running.
2. Check for restriction or air lock in fuel lines, and correct all fuel leaks.
3. Clean or replace air cleaner/filter if necessary.
4. check return line non-return valve for proper functioning.

Regards,