ZINGGG

Take it to a parts store, have them pull codes and see if anything is stored.

Test fuel pressure at the fuel rail using a fuel pressure gauge. That crappy Airtex pump could very well be your problem.

What else have you done in the past 11 months since starting this thread? (seriously, list everything) Ever replace the coil? Ever replace the wires, cap or rotor? How hot are you running?

cmarr6

The fuel pressure regulator is located at the front of the fuel rail. It is a little round thing with a vacuum hose running to it. Very easy to change. One 7mm bolt that hold a bracket that holds the regulator in. 5 minutes tops. Just make sure you get the little o-ring out of the inside if it doesn't come out with the regulator. Don't ask me why I say this It is kinda spendy though, $70 for the little f-ing thing, but well worth it if that is the problem.

Hatrick

Ok Guys I read this post and two others, yours sounds like my issue.
I've been suffering the problem for 2 weeks. I rebuilt the top on my motor in sep 2012. This should not be happening!

So I'm just gonna post my issue and then followed up with the solution to my problem.

Driving when accelerating my 1992 4.0L started to spudder at around 2400 rpm, Hot cold no diffrenance, loss of power and spudder city. It was initially fine from the idol speed to 2400RPM then starting the second week, like crap mine started to spudder all the time. It got progressivly worst over the second week. What dose a jeep owner do... he reads and reads and reads.

This issue was acting like it was a fuel issue. It was not. All the symptoms were leaning leaning toward fuel injectors. But that was not the case.

Since i just rebuilt mine in September I replaced Plugs, wires, rotor and cap less than 5 months ago. So I did'nt even bother checking them.
I read several posts but never once did anyone mention check the distributor tightness! OMG!

I opened the hood after driving tonight, the motor was idoling rough. Just looking in the engine compartment and I was compelled to see if i could twist the distributor cap. I grabbed the cap while it was running. (No im not a scared!!) I applied a little clockwise torque on the distributor and it died instantly. I grabbed the cap after it stopped and it rattled in place! The distributor was loose! 1/2 inch shorty and 5 min later it was securly in place.

Took it on the freeway for a 5 mile, heavy footed test drive and it runs like a stripped ape! Back in business!

Hope that helps someone.

92XJGuy

So the sputtering has gone away. It went away after I got more gas and seemed to be happened when I was low.. although I don't know for sure if a full tank fixed it. However, my hard idle seems to be sticking around. I started it up today and it revved a little high, stayed, then went down.. Then when I sit at lights, you can feel the idle. Now also, my driveshaft is unbalanced and was my friend's beater shaft lol. We needed a front XJ shaft for my hack n tap. Any thoughts?



Cheers




I'll check mine out. Can't hurt. Thanks!

I'm leaning towards fuel pump.. The plugs were replaced before this started happening. I think I have a new ignition coil in my glove box I can swap out. I haven't replaced anything, really. I'm running at like 160 or so. I think the middle is about 212, I'm always to the left of it at that line. Thermostat was replaced last summer as well.

92XJGuy

So, I wanted to give an update.. My issue doesn't happen much if at all when I have a full tank of gas. I also noticed when I was driving on the highway for about 20 minutes straight, no traffic, so I was hitting 60-70 the whole time, nothing happened. But when I got off the highway to take the roads home, in stop and go at lights, it started happening a lot. This also happens mostly at night.. think that has anything to do with it? lol

92XJGuy

Any ideas guys?

JerrytheJeep

I had a strange issue with sputtering on a highway trip, got home to check it and noticed a whining from my dizzy. Replaced the whole thing, good as grass. The bearing was seized like crazy. Caused a strange sputtering under acceleration and I had to floor it to get it to go.

Another thing, clean your throttle body and sensors. Check your tps, clean your IAC, make sure your intake is clean and free flowing. I broke my map tube the other day and it ran like horse ****, fixed it and it ran fine. To check it, let the car idle then remove the tube, if it changes you're fine if not then replace the tube. Also make sure the grommet thing on the throttle body is in all the way. If you have a broke o2, change that as well. your ecu uses the signals from there to control your mixture. You are having mixture (or firing) issues.

JerrytheJeep

Have you changed your fuel pump yet?

goofyjeeper

pretty sure this is my problem, although, mine ran strong, no sputtering or anything.. ran great, then i slowed up at a red light, went too accelerate, and it just dies, start, wont stay started..

but, reading all 5 pages of this thread, if your fuel pump is whining, usually means it's going bad.. and i have a 92 as well, pushing 226*** miles, so gotta remember, as awesome as this 4.0's are, things doo get old and tired after a while, especially running cheaper gas.. so especially after doing a tune up(which i did, and didn't help), then i'd b focusing on that fuel pump, and the regulator.. if ya gotta buddy with a Cherokee, just jack his regulator, be better then throwing $70 at it, and possibly not being able too get ur money back if it don't help.. just an idea... but hope you get it fixed for good soon.

92XJGuy

Is there a pic that highlights the map hose so I know what to replace? Also what kind of hose is it? I replaced my heater control valve with two different types of hoses, so I'm assuming it's like that? Also my O2 sensor has been broke since October. Although this issue just started happening earlier this year lol.

I have not. I have a Bosch waiting to go in.

I'm thinking it's the fuel pump showing symptoms of going bad.. It's an Airtex, so that doesn't help. I have a new Bosch waiting to go in.



Cheers guys!

Perrin Pockets

So I have a '98 4.0 Sport, my RPMs have been bouncing a bit since I bought it (about 2 months) so I decided to start doing a tune up. I changed the plugs (gapped at .035) and all new wires and new filter. I go to drive around the block and ive lost 4-5mpg and is now sputtering, bucking and unresponsive. I've never had any sputtering or bucking of any sort before. 2 weeks ago I welded up a mag. cat and flow supper 44 (love it so far) during the install I had to cut the O2 sensor wires to get the cat down (didnt have room to get the clip out...bad idea I now know) Ive been having to prime for start not long after and CEL poped on so I had it checked and was told O2 (i knew that) and fuel pump. I was planning to get the O2 later this week. I wanted to start with a tune up and this is where i ended up. Should I get the coil next, O2? or fuel pump? (whole assembly or just pump?) please!

JerrytheJeep

You should have made your own thread.

Not having your o2 sensor is going to make your motor run very poorly. Get that fixed first.

Perrin Pockets

So I feel like a total moron, and as embarrassing as it is to say... I apparently broke 2 plugs in the process of changing everything. I will add I am a nube and this is my first time changing spark plugs (try not to laugh) but I am learning and it's only going to cost a few bucks to replace them and I'm good so that's fine with me. I am still replacing the o2 sensor during the week as I know that's causing problems too. Thanks for the time

96xjshaggy

I have a 96 and it also has a bad sputter when i accelerate hard to get over/pass someone. Feels like a manual and i can't drive lol. Also when i get on her in the mud will barely spin tires just bogs down and a horrible clunk/knock noise from front left. Any pointers will be grateful.