I've got a 99 Xj with 234,000 miles that wont go over 25mph unless I'm going down hill. I can see the rpm gauge jump around when I get to that speed and can feel the jeep lunge and jolt around as it cant go any faster. I already replaced the CPS although it was replaced a year ago anyway. And the jeep has no CEL. My fuel pump appears to be fine as well as I can hear it turn on with no different sound to it then usual. I dropped it off at a good mechanic who I've trusted for years (although I typically do most jobs myself) and he thinks its my timing chain. What I'd like to do is get some opinions from people who may have new ideas or have seen this before. I will be the one who ultimately replaces the timing chain and because this jeep has been my DD for years Id like to get the job done quickly rather than fumble around replacing one thing after another and get back on the road ASAP. My mechanic has already replaced my distributor and doesn't seem to think its fuel related. Those were my immediate guesses.

Only other thing I can think is that months ago I replaced my flex plate. After changing that out I had an issue where a bolt would come loose between the trans and the block on one side and that would actually cause these same symptoms. Only difference is this time the bolts not loose, everything is tight and seems to be functioning as it should. I even pulled back the inspection plate. No shavings and the flex plate bolts are tight too.

Thanks in advanced. Its been years since I've posted on this forum. I look forward to any responses. (and I hope I posted this in the right section.)

Take it out of 4-low? Just kidding. Man I can't see a timing chain stretching so far that it causes that big of a problem. Not saying it is impossible, just that I suspect other issues. It almost sounds like a transmission issue. Or a torque converter issue. If you leave it in park will the engine rev up just fine?

I wouldn't be entirely shocked if it was the torque converter actually. When I had the transmission out for the flex plate swap it seemed as though the inside of the torque converter had a lot of play in it. Although at the time I thought it was odd I'd never been around a torque converter before and simply put it back in. I've put 3k miles on since I put the trans back in with the new flex plate.

Is your catalytic converter clogged?

Good suggestion. I had that happen once and the engine will barely run.

I hadn't thought of that. My exhaust dumps right after the cat. Its still stock. Definitely an option.

I think that's going to be the next thing I replace. Do you think it would be throwing codes if this was the issue? I don't have a CEL.

I didn't end up replacing the cat yet. I decided actually to drive it as is in hopes eventually I would trigger a check engine light.....and I did. code reads p1391. So I called my local dealership to get a mopar original CPS and although I've replaced it before I've never done it with one of the "good" ones. So that's my next move.

Test stuff:

http://cruiser54.com/?p=98