96 F-150 Starting Problem

I have a 1996 F-150 (6 cyl, 5 speed). The truck has no problem starting in the morning or when it is cold (winter) however after driving it around the truck barely starts. I have a new battery and new starter in the truck. When the truck is warmed up is when it wont start up again or takes 3-5 times to get it running. It cranks and fires up but then sputters and ideals very low then shuts off. I have to try and start it 3-5 times until I get it to ideal smoothly then I can rev the motor and it's fine. Not sure if its the fuel pump or fuel filter.

Does anyone know what the problem could be and how to fix it?

Thanks,
John

well quite possibly a combination of the both. The filter though is a whole lot cheaper and I would start there first. you may also check your rotary button and cap. alot of times when they age and "blister" the engine will be rough etc until warmer.