need some help 6.5
 

my buddy just picked up a really nice single cab 3/4 ton 4x4 with a rust free body and new rims and tires. truck sat for about a year with not much fuel in it, and it was running and driving but running rough. i changed the fuel filter and drained the water from the water seperator. ran like a top, no more skipping and hogging up, for about 50 miles... now its right back to it skipping and is absolutly gutless. any ideas?

I'd change the fuel filter again and ensure that the lift pump works when the engine runs.

It would help a lot to know what year it is-they are not all the same.

problem solved, it was the pmd