92 B2200 fuelie cutting out? HELP!

Well ive tried everything, plugs, wires, cap n rotor, fuel filter, timing belt (also the timing is perfect). when it runs right, it runs great, but most of the time if i speed up or am going down the highway it feels like a loose all power or cuts right out. My truck smokes as well and i know i might need rings but i didnt think that would make it run like shit so i thought maybe fuel pump??