I have been told my throttle position sensor needs replaced?

i drive a 1993 chevy s10 blazer tahoe LT, its got the 4.3l vortec v6 and it has its problems, like sometimes (after its warmed up) it misfires and spits/sputters, sometimes when im in town at low speeds ill romp on it and it studders and barely gains speed unless im to the floor, it will "skip" when i go to powerbrake a burnout or get on it, (skip as in shake and run rough, like its got a dead cylinder or misfires really bad) the exhaust will sound like its backfiring sometimes too.... could you guys please help me? im gettin tired of messing with this truck, though its a beast for the first 10 or 15 minutes of running....