My 94 jeep grand Cherokee 318, 5.2 liter all time 4wd hesitates in reverse and drive. What causes this

Check air filter and clean throttle with throttle body cleaner spray also replace fuel filter if have not done so in a while. Add fuel injector cleaner to gas tank.

Sounds like you may have a leaking servo inside the transmission. The leaking servo causes the low and reverse band to engage slowly. Once the pressure rises enough to override the leaking servo your Jeep will start to move as the band is applied in the drum.