I have owned my 2000 XJ for a little over 2 years now and it has always had this irregular idle.

It cannot be heard, it is not a big surge and it is not a misfire. Every few seconds at idle the rpms will either move up or down about 50-100 rpms.

I have done countless repairs to the jeep over the years, but the somewhat relevant ones are these:

4-pin injectors
new Mopar TPS
new IAC
spark plugs
previous owner changed coil packs right before I bought
Rear evap lines replaced

No check engine light, it never comes close to stalling or anything. Literally just moves maybe 50-100 rpms gently up and down every few seconds.

I am probably selling the jeep in a few months to upgrade but in the meantime if this could be fixed that would be awesome. Any suggestions or do I need to live with it?

Multiple mechanics have told me to just leave it alone, it is an archaic motor (4.0) and it has its quirks.

 

that is pretty normal. my zj and my dodge both fluctuate by that much.

 

Thanks for making me feel a little better, it just pains me that my friend's XJ with 215k+ miles doesn't do it and I bought mine at 80k and it has been doing it all along.

 

There are people with wayyyyyyyyyyyyyyyy worse problems than this that aren't worried about a thing and you're concerned about a 50-100rpm gentle rise in RPM lol. It's alright, file it under "it's a jeep thing"

 

Haha yeah that is actually a big reason I am going to get rid of it, I'm not the type of person who should own an XJ. The interior creaking noises drive me crazy, I aim for perfection.

If you want to buy a super clean stock 2000 red XJ with 97k miles let me know
Not 0331 head, had it replaced with a brand new head at 80k, insane list of new parts all documented with dates and mileage of repair. Located in New York

 

You could try the "steam clean your engine" trick. I think it's in the how to section now if you don't know what I'm talking about. Might make a difference, might not. Just my 2 cents.

 

Im a sucker for clean XJ's.... but your's has a weird idle issue so I'm going to have to pass on the offer hahaha I'm kidding. Post it up in the classifieds. what are you asking for it?

 

Yeah i've been thinking about doing that, thanks.


And I am not really to sell it quite yet, but when I am I will put up a post. Can't let it go for under 4,000. It has a rebuilt title because it was stolen many years ago. If no one wants it for my price I'll just have to hang on to it.