I have a 95 f150 with the inline 6, and lately the truck has been shuddering whenever I am half on the gas but it will stop when I put the pedal to the floor. Would this be a timing issue?

 

sounds like a high speed miss. at night start your truck and open the hood check for spark from the wires under throttle. should see spark arcing towards some metal on the engine. also could be fuel filter or air filter or fuel pump. try putting a cap full of oil in the gas tank. Dont laugh it works a times. ethynal gas is bad bad bad the oil helps keep seals and such from drying out. timing dosnt usally go out unless timing chain is stretching.