I have a very odd problem on my 99 xj. For the past month or so I would run into the problem that when I am driving down the highway, my jeep would sort of buck (almost like i hit a pothole that didn't exist, nothing violent.) It would also hesitate slightly at takeoff from idle. Then one day I was driving at 55mph and it did the buck twice and a few seconds later my tach drops to 0 instantly and i loose all response from gas pedal. Jeep slows down all the way to idle, but never cuts off. I got it to the side of the rode and sat at idle for a few seconds until the tach all of a sudden pops back up to idle and i suddenly have throttle response again. No check engine light that time.

It was almost a week before it bucked again. Then almost a week again before the rpm drop happened again and this time the check engine light came on, but when the rpm came back, the light went off instantly.

Any ideas? I am almost sure its something electrical. I fixed the hesitation by changing my throttle position sensor. I also have since change plugs, plug wires, dist. cap, and rotor button.

Any help would be much appreciated.

 

messed with grounds to battery and with fuses. i had changed plugs, wires, rotor,and dist. cap. it did it once directly after i changed those. but has not done it since. this was like 2 weeks ago. bad wire? bad plug? ground? i dunno just hope it doesn't come back.