This only happens at 65mph. If I let off the gas it goes away. If I go faster it goes away.

At 65mph it hesitates. Feels like the Jeep is bucking back and forth, or "trailering" for those that might know it under that term. It started after I replaced the shocks and installed front/rear bumpers. But I was under the assumption that the summer gas here in Vegas sucks. On a recent trip to Northern Utah it did it on the freeway as well. I run 87 octane in Vegas and 89 octane in Utah (not the 85 octane they sell). I replaced the fuel filter before the trip (after 20k miles from previously) and after the trip with only 3k miles on it. Both times were clean, but the filters are cheap anyways.

I also replaced the TPS, cleaned the IAC and cleaned the throttle body. All with no luck. Fuel pressure is good. The plugs are clean with only 15k miles on them. Wires, cap and rotor were replaced at the same time. No codes and my scan tool does not show anything out of the ordinary with any sensor that I can read live data from.

I'm not sure if the alignment has anything to do with this. My caster is off by a lot now after installing the Fox shocks. The front axle sits a little further back, but i didn't think shocks would cause that. Sitting at ~4.5" lift on 31s, SYE, C8.25, open diffs, 3.55 gears...

I am at a lost with this now. I drive it everyday and it seems to be getting worse now at that speed. Any suggestions?

 

My 95 XJ is doing the same exact thing. I will tackle the Crank Position Sensor next. Done a complete tune up, new O2 sensor already.....which helped the idle tremendously.

 

My 94 xj had similar symptoms. Tried to cut out when hot. Farted about. Pulled up. Totally cut out when parked up. Had to wait for it to cool down to restart engine. Replaced cps and it's as good as gold. It suffers from thermal breakdown. Steve.

 

Thanks guys. The CPS is original at 150k miles and 17 years. Possible that it could be slowly going out.

Anyone have problems with AutoZone or O'Reilly Auto for that part?