hard time starting

[walkinhorsepowerstroke]

I have a 2004 f350 6.0 with 139,000 miles on it I have to pump the fuel pedal in order for it to start and stay running, runs rough and has a hard time goin over 20 miles per hour then takes off and runs ok whats up with this truck

[jesilvas]

Pumping the pedal does nothing for starting, that's only with a carbeurator.
Sounds like you might have a weak FICM, injector stiction, or other things.
What type of oil do you use? Oil filter? Oil change intervals? Battery CCAs? What temps is this happening in?
btw. All those answers will help in diagnosing what it could be.