Been having this issue for a little while now. I had thought that I had fixed the issue after reading a couple of posts on here and taking the corrective action. The problem went away for a couple of tanks of gas but is back again.
A little history, I had a check engine light for a leak in my evap line and fuel pump not getting the right voltage. I replaced the fuel pump and the evap line from the tank (rusted through) and that appeared to fix that problem. Meanwhile, the Jeep had been hesitating and bucking, not all the time. It would do it for a minute or two and then go away. I had thought that it was the pump because it might not have been supplying enough fuel. But the problem remained after the fuel pump replacement.
After the fuel pump, I unplugged the upstream O2 sensor to see if the sensor was the problem. The bucking/hesitation was still there,. Again, it would come and go. I then cleaned out the throttle body and the plunger, no help to my hesitation/bucking. I put high test gas in to try to clean things out. I also went as far as seafoaming the engine (I have heard very mixed reviews about it but I was quickly running out of options). After this, it appeared that the bucking/hesitation went away.
I went a couple hundred miles and there were no issues. I just put another tank of gas in the Jeep yesterday and the bucking/hesitation came back. It also almost stalled out when I was driving. It took a little bit for the Jeep to warm up and then it came back full force. Appears to happen when pressing the gas pedal. Although before I replaced the pump, it almost stalled out when I was at a light. I've run out of things that I know of to do. What do you think is going on?