I've got a 98 XJ Classic with around 125K. Well cared for, regular maintenance.

This problem started a couple of months ago and has been an infrequent, intermittent problem. Wondering if any of you have come across this issue.

I'll be driving along at around 15-25mph and then it seems like the engine starts to get unresponsive to when I press the gas pedal. It begins to sputter, as if it may stall, and pressing on the gas pedal further to try and force it causes a "pop" or "knock" from underneath the vehicle but has no effect on increasing the speed or engine rpm. When this is happening a) RPM guage fluctuates, and b) I cant get the car to go more than 15-20 mph. The car will lurch, choke, pop... lurch, choke, pop along... After 1-2 minutes whatever causes this problem just passes and *presto* the car then runs normal.

Observations:

1. Doesnt happen while on the highway. At least, it hasnt happened yet while going faster than 25mph.
2. Doesnt seem to matter if engine is cold, or has been running for a while.
3. This problem is infrequent. I can drive for days in a row without experiencing this, then a day when it happens twice in one 25 minute trip.
4. Except for when this issue happens, the engine sounds as if it's running better than ever!
5. Once it actually caused my engine to stall when I pulled over to the side as it was happening, but when I put into Park and went to start her up again she started up fine, and the problem was gone.
6. There is no "Check Engine" light when this issue occurs... for what it's worth.

I am thinking it'a a fuel delivery issue, but I'd like to get some other suggestions. Anyone have this problem?

NOTE: This past fall I replaced the fuel pump but did not replace the fuel filter. My father (a longtime jeep owner and self-taught mechanic) tells me on the phone he's pretty sure it's my fuel filter full of crap. I initially thought it might have been bad gas. No such luck!

 

i see this problem alot on here and most people point to the CPS (Crank position sensor)....

Is there a specific fuel level when this happens full/half/quater???

 

Enders cherokee was doing the same thing. I told him to replace the fuel filter and sure enough the the stalling an drough idle were gone. $13 good luck

 

I had the same issue with my 98 xj , turned out to be my o2 sensors , never a cel light. Drove around for a weekend with a scanner and caught it. Fyi the upstream o2 sensor harness plug had some green corrosion, this was prob the cause. Replaced both sensors and havn't had a problem since.

 

98jeepsrt6: it seems to happen at or below half, but maybe thats coincidence.

My wife has the car today, she just called to tell me the yellow Check Engine light popped on while it was happening, so I guess I can pull the code and see what the issue is.

Thanks for the replies and suggestions, I'll post back in a few days when I figure out what the issue was. Or get it back from my mechanic