No expert here, but I had a similar problem and after a few replies, guys helped me solve my problem. I replaced the upstream O2 sensor and cleaned the throttle body. Not sure which one fixed the problem, but its gone. Been driving the car for two weeks and no hesitations at all. I believe.....but don't quote me, that if you give the jeep full throttle and it DOES NOT hesitate, then its the sensor....and that was the case with mine. Just cleaned the TB as a precautionary measure. Again, I am no expert, just what worked for me.