Picked up my first Jeep, a 98 Cherokee Classic with 190k to be my new DD and weekend camping rig. So far I've done plugs and wires, oil change, and a coolant flush (not entirely successful, but its cold as could be in the driveway).

A few small things on my to-do list are a heater core flush, checking the relay for the rear wiper(only works if I press down all the way, no intermittent), and check the factory fog bulbs.

After the nice 16" of snow SE Michigan got yesterday, I was in love with the 4hi on my girl, flawless! Until today on my way home from work when I noticed it jump out of 4 and into 2hi. 4lo and 2hi work, just falling out of 4hi. No biggie, a little linkage adjustment and I should be all set.

My biggest issue right now, is that if I start it and let it warm up, the RPMs will drop every little bit and sound like its about to die, but never does. Then if I take off before its ran for a few minutes, it gets jumpy on the throttle and will feel like it is stalling, make a strange clicking through the gas pedal, and then tame off again. From what I've read on here, that could be an O2 sensor issue. Is there a way to inspect the O2 sensor, or should I just replace them and be done with it?

Thanks!!

 

Is it an auto transmission ? If so, it may be a good idea to change the oil in that also.....Dexron-Merc type stuff, about 4 quarts, and check the level in the transfer case and differentials .....

 

Yes, its an auto. I will go ahead and change it and look for metal in the fluid. I will also double check the diff's. Thanks!

 

Nothing to inspect on O2, should be a test value tho. CEL/codes??
Wouldn't hurt to clean IAC and throttle body.

Don't think we got 16" in Lapeer

 

Its not throwing any cel, which confuses me with the way it opens up after warming up and drives like normal. I'll take a look at the throttle body and IAC though.

We got a solid 14" in Harrison Twp and it was around 16" in Detroit.

 

So after a little while of not really having the stuttering/feeling like its GI
going to stall issue, it has returned even worse. Before, if I let it warm up for a minute, I wouldn't see the issue. Then last night on my way home from work/running some errands, I noticed that the idle was very rough and sounded like it was missing a bit. No worries, give it a little gas, and it runs like a top. Then at a light, it dropped and shook the whole jeep and then the idle jumped to 1100 for a few seconds and then settled back to a smooth 750~. I recently pulled the entire intake valve assembly and cleaned it up real nice and cleaned the IAC up real well. Its not throwing and codes or CEL, so I'm not sure where to begin at this point. A few threads have said TPS, a few have said MAP, and a few have said CPS... I'm not really wanting to spend $$$ on sensors to MAYBE solve the issue. If that's the only solution, I guess that's that, but I would love some suggestions. I've also thought maybe its an O2 sensor, but from what I understand, it doesn't take input from them until it has been running for a bit, just running on preset parameters.

Any ideas?

 

Cap and rotor? Clean the throttle body?

Inspect your motor and trans mounts. If good, go ahead and adjust your transfer case shift linkage.

Make sure there's fluid in the transfer case!!!!!!

 

TC is good, did the drain and fill a couple weeks back. Trans and motor mounts look like they are going to be added to my list for the summer, and the TC linkage works again, had to find the sweet spot. Plan is to replace the linkage over the summer, not a high priority now that the snow is gone. TB was cleaned, even pulled the valve plate and scrubbed the inside. Doing cap and rotor tonight after work, but I feel like there would be issues at any RPM if it was that, not just idle? I could be completely wrong, still fresh to the Xj world

 

Don't over think things when it comes to maintenance. Just do it like you have begun to.

 

Did you ever get your fuel injectors squared away?


There are situations where a leaky fuel injector will cause the upstream O2S will sense a rich mixture and cause the PCM to pull fuel off, causing the other cylinders to run too lean of a mixture, which will cause a rough idle, borderline misfiring, and you may see a stumble when accelerating from a stop. At higher RPM (2,000) this situation is less noticeable.


If you had a Scanner that shows live data you could see the fuel trim. If the above is true you would see negative (-) fuel trim numbers at idle and more towards zero (0) trim at 2,000 RPM.

 

I will have to give that a look when I leave work. I use the Torque app to live view, so I'll check the fuel trim at idle and see what it reads.

I did a SeaFoam treatment as well as cleaning the TB and IAC which seamed to have a slight positive effect with the rough idle, but I may have just dislodged some gunk that's now blocking an injector. I have a set of 703s soaking in SeaFoam at home waiting for my rebuild kit to show up probably Saturday so as long as I don't completely screw it up, I should be installing the upgraded injectors Sunday.

 

Replaced the rotor and cap tonight and double checked the gap on the plugs. Cap looked like it may have been replaced not too long ago and one of the screw holes was pretty much stripped. I'm going to pull it off again and try to fill the hole with something to give it a tighter hold. The rotor was the original Mopar and the contact point looked pretty beat. All of the plugs were fairly close to 0.035, but I set them all to 0.035 exact.

I noticed today that my skinny pedal feels tighter than normal if that makes sense? Like there is extra resistance on it. I'm going to see if I can spray some white lithium into the cable run tomorrow, I don't have any at the house. I also noticed while I was in the engine bay that my kickdown cable adjuster is shot. The inner piece moves freely in and out of the housing. Is this something I can replace fairly easily with a jy part, or will I need a brand new part and some well lit work space?

Back on to the stuttering issue.... The cap and rotor didn't help much. I am now leaning towards one of those three not so cheap sensors on the throttle body(IAC, MAP, TPS). I'm thinking the TPS seems the most probable?

 

Why replace parts when you haven't finished troubleshooting.


You said you are going to check fuel trim (?)

 

Might try blue locktite on that screw.
You've cleaned TB and such?

 

Whoops, forgot about that. Yes, checked trim on my way home and like you said, it was going between -1.6 and -3.6 at idle and went up to +1.6 coming away from the light and settled to 0 once I got up to cruising speed.

Cleaned the TB and IAC real nice.