I've been getting horrible mpg to start off with, also after driving for about 3-5 min my 4.0 chuggs bad, then goes away after about 5 more min of driving. ran the codes that I had, there was a shit ton! cam pos, low volt from the coil pack, miss fire on left bank, so I had them cleared, drove about 150 miles the light came back, expected, but I wanted to clear the codes to start fresh,
So I checked the fly wheel sensor, the wires looked as tho they had been striped, I didnt have any extra wireing to redo the wireing so I just used some heavy duty shink wrap and electrical tape.
took it for a drive, seems to have more power and no chugging. For Now!!!