97 Jeep Grand Cherokee surges and idles rough. Please help

Hello, I have a 97 Grand Cherokee with a 4.0. The car has about 130k miles on it. I can drive the car sometimes and I have no problem. Then usually seems like when its hot after awhile of driving like going up hills or on the highway going up hills the car with start to surge and sputter like it has no power. I will pull over and it will idle like crap and not stall but seem like it wants to. If I shut it off and restart it, the car is fine again for awhile. Seems like a fuel problem so I replaced the entire fuel assembly in the tank. Fuel pump, regulator, filter. Whole thing. Didnt make a difference. The car had a full tune up not too long ago, but I dont think it could be anything like that cause it doesnt always do it, and when it does if I pull over shut it off and turn it back on its fine. Weird. Any thoughts? Thank you for your help
Jon