1989 Ford Bronco Crank Truck Exhaust Sounds Real Hesitant Put Reverse Back Out

when i crank up my truck my exhaust sounds real hesitant and when i put it in reverse to back out it shakes and jerks and when i take off it is hesitant to take off unless i lay on the gas. when im driving down the road it will kind of jerk back and fourth. what could this be?
the engine was replaced and has about 50k on it and the transmission was rebuilt and has about 15k on it