Hi, I have a 1996 Jeep cherokee 4.0 I6 4x4. 5 speed manual.

Recently it started "lurching" at highway speeds, they were very subtle at first. They felt as if the gear would slip for just half a second and grab again. Also, they would not occur at lower speeds. Recently, on a longer road trip, the subtle lurches became full on jumping at all speeds.. as if I was a beginner learning how to get rolling in 1st gear. Check engine light came on, P0300 and P0305. Random misfire, and misfire on cylinder 5. The lurches are so bad it seems as if the motor is seizing. However, it will only happen at full operating temperature - Will run and drive flawlessly until it comes up to temp.

Due to my situation when the very bad lurching began, I had to run the jeep another 20 miles to a decent area. I thought for sure the motor would seize before the 20 mile mark, but it made it. Upon getting the jeep home, I checked the oil. No antifreeze, metal shavings, or burnt smell. Oil is beautiful. I have since changed the fuel pump, but it did not change a thing. Runs fine at first, but lurches like crazy as soon as temps come up.

Any thoughts? Any advice is greatly appreciated.

 

When was the last tuneup?

 

I did the distributor, cap wires, oil, and antifreeze about 2000 miles ago.

 

Could be the TPS is going bad and causing issues.

 

Start by checking the fuel pressure.

 

No plugs?

 

Did you PUT a distributor in it, or just the cap? Is the distributor bushing loose? I just put a dizzy in mine, and was expecting improvement in the ignition, but also got a nice surprise, the lagging between shifts when it reaches rpm..automatic tranny..is gone

 

Thank you for the input guys. I did do plugs at the same time. Also correction, I only replaced the distributor cap. I do not think that timing is part of the problem, primarily due to the fact it will only begin to run terrible once it heats up. Timing would not be affected by temperature.. would it? I will check fuel pressure in the next few days once I get time, as well as the TPS.I'll let you know what I come up with. Thanks again.