pineapple_tree

I’m not sure really. The valve train noise I’m hearing is sort of a clattering that doesn’t happen rhythmically, it just sort of makes a clattering sound around idle. You can really hear it with the windows down sitting at a stop light or a drive through, and for right now it just seems that clattering is just a noise. There’s a possibility that this clattering noise could be causing my issues, but I plan on doing a small top end rebuild, and i’ll take pictures on what I find.

pineapple_tree

Okay. Here’s another update.

I changed out my TB gasket and the IAC motor, and now it hasn’t sputtered once. I drove it a good 20 miles today, lots of random acceleration in 1st and 2nd, and no sputtering.

I’ve been having an issue of my idle changing after i’ve been driving, and basically it would idle really high after I go to neutral, and then it would calm down when I stopped. I’ll keep a check on everything and see if the sputtering comes back, but for now, it’s gone. Which is bizarre.

pineapple_tree

I managed to reproduce this issue by letting it run low on gas. I’m running my tank to near empty to fill it up with ethanol free gas, and i’ll see how it likes that.

Essentially, if i’m starting on a hill, it will sputter until it levels out, when my tank is below a quarter. I also discovered that when i’m running low on fuel and I stay in 3rd gear at about 15, and go pedal to the metal and lug it, it will sputter really horribly, but only does it about once every 2 seconds doing what I just described.

This makes me think that whatever is causing this is fuel related, and I’m thinking it’s more than likely an injector not firing correctly, considering they are the original Siemens injectors.

If anyone has a set of injectors, part number 0280155710. I did a crap ton of digging and this appears to be the only ones that can work with my 2.5, being OBDI. I want to upgrade them to the 4 hole injectors. I’ve heard they do wonders for this little engine

pineapple_tree

Well, now i’m pretty sure I found the issue. I was looking for the wires to the power steering pressure switch, and I finally found them, but at the same time found exposed wires leading to the o2 sensor. The PO had tried to tape them up, but it didn’t do anything. All of the wires had been cut and taped back together. I had been getting code (21?) for the o2 sensor not being detected, and i’m pretty sure that was because the wires were shorting together. I cut them, stripped them down, butt connected them together and heat shrunk it, started it up, and almost immediately my Jeep felt worlds different. Acceleration is more smooth, my gearshifts feel better, and it no longer sputters in any gear, even if I lug it up a hill in 3rd. Even after I filled it up with gas, it was sputtering in 3rd if I gave it too much throttle.

What I think was happening is that one of the wires was shorting either the heater or the sender wire to ground, causing the computer to revert from one table to another regarding fueling. If the wire was shorting it out on and off, that might cause sputtering because it’s acting like it’s being unplugged and plugged back in.

I can’t express how much different my Jeep feels. Even my girlfriend said it sounds more healthy and is really smooth and responsive when accelerating. And now, with upgraded injectors on the way, hopefully i’ll get the best out of both worlds.

jallen9339

You know, from the start of your post, it sounded an awful lot like an o2 issue based on my experience. One of the first problems my 98 XJ had was hesitating when accelerating through the low gears (only 1st and 2nd). All that went away when I replaced my upstream o2 sensor. Pretty sure it was the original (98 model, 120k miles), so it was definitely time for a replacement. I didn't use a good sensor, I found a cheap pair off Amazon for $25, which may prove to be a mistake, but it sure fixed my problems. Glad you figured it out, always a relief.

pineapple_tree

What confused me was that I just replaced the upstream sensor with an NTK OEM one. At one point I thought it was defective, but that’s kind of rare for an NTK O2 sensor. I drove the hell out of it for last day or two, and it feels like it’s never felt before. Especially on hills. Normally it lacked going uphill, but now it takes them like the champ she is

pineapple_tree

Well, it's safe to say that this sputtering issue has been fixed. I've driven it about 300 miles since then, and not a single putter or miss or any kind of sputter. So if anyone needs help, it's more than likely one of two things:

O2 sensor itself... not a very expensive part to replace, and y'all OBDII folks can diagnose it easier than me, but honestly, you should just replace it if it's never been done.

O2 sensor wiring... make sure the wiring isn't exposed or cut or just taped together. You never know what someone else did under your hood, and sometimes it's worth checking most wires, as these XJ's get older.