94 F250 5.8L is running rough when in OD on slight hills. If I punch it, there's loads of power. If I take it easy, the truck runs really rough. It started suddenly the other day. Any suggestions?? I thought about the fuel filter and wonder also if anyone could comment if there's a trick to separating the fuel lines from the existing filter??

 

I am thinking more along the lines of a plug or plugwire. They will show their weakness the most under a load at lower rpm with the torque converter locked up.
A good tune-up is probably is needed.
Jimmy