1996 drivability issues

so ive got a 1996 4.0 xj that randomly almost dies at a stop and cuts out while cruising. when i first got it, it ran fine, except after running on the freeway it would sometimes just run rough. i pulled the distributor cap and found the shaft bushing was bad, so i replaced the distributor and the running rough problem went away, but now i have this almost stalling problem. while sitting at a light it will just cut out and almost die (does die if the a/c is on) and cuts out while driving but because rpms are up never dies. it starts right back up if it dies. there are no engine lights on, few weeks ago i got a random cylinder 1 misfire, and an injector code but never came back. im either thinking i got a bad distributor or it needs a crank sensor. thoughts? recently its also developed an extended crank issue but i have found its bleeding pressure after i shut off. i wouldnt thing that would have effect on my issue?

CPS would be one candidate.

I would also be inclined to put on a fuel pressure gauge and make sure it is holding 49psi. How old is your fuel filter?

If that checks out good it would then be time to put on a scanner and watch the sensors in real time.

I have never had to deal with it myself, but I think I have seen some discussion about cleaning the IAC. Probably would not hurt to look into that. Probably a cheap maintenance operation.

Checking engine/chassis grounds and battery connections would also be a cheap, maintenance operation.

Two cents worth of SWAG.

it holds fuel pressure at idle, i havent checked driving and i have cleaned the IAC. I will check for loose grounds and wiring issues as well.

Subscribing...

Chasing similar gremlins....

There was a rash of coil failures on the mid 90's XJ's awhile back. Seemed to be heat related, when the coil got hot it would get flaky.

My coil is still OEM, I've been expecting it to crap out in my 96.

Your issue kind of sounds like the IAC. Mine has a tendency to act up when I have a battery or charging issue. It is usually the first indicator something is wrong with my battery or charging system. It starts acting up before I notice anything drastically wrong with my battery or charging system, kind of a precursor.

I also had something similar when my front O2 sensor was on it's last legs. I didn't get any codes on my O2 sensor until it completely crapped out. The IAC won't throw a code.

One sure indicator of a bad O2 sensor is if you get a stutter/stall the first couple of minutes after a start up. But this may also be a gummed up IAC, the oil and grease buildup on the IAC gets thinner as it heats up and the IAC may work better.

You may have multiple issues.

Sounds like a classic case of Throttle Position Sensor, or TPS. Been there, done that on my '96. Be warned, however, the ones that I bought at the auto parts store were, in my experience, crap. I cross referenced the part, '91 to early '96, XJ and ZJ were compatible, so I went to a local u-pull-it, and stocked up. Got six, paid five bucks per, and weeded through the lot till I found one that most closely matched, electrically, the one in my '92, which always behaves. Be aware, though, that the Cherokee 'Classic' models MAY have the wiring harness and plugs from the '97+ models, and might not be 'plug and play'. Just part of the Jeep Thing....

Iac will not cause problems at cruise, only at idle. When was the last time you did a tune up? Plugs, wire etc.

Start with the basics: Are all the tune parts fresh ? Test the coil. Test the TPS. Test the CPS. Test the O2 sensors. Test the fuel pressure. Clean and check all the wire harness plugs. Inspect, clean, and snug all the battery/alternator wires and wire connections. Clean the IAC.

Only buy genuine Jeep engine sensors and NTK 02 sensors.

The Taiwanese built Hall Sensor (cam position sensor) in the Parts store distibutors is suspect....had the same thing going on with mine. Re-installed the OEM sensor into the "new" distributor cured it.

trippled said:

Iac will not cause problems at cruise, only at idle. When was the last time you did a tune up? Plugs, wire etc.

Click to expand...

Throttle open IAC closed, throttle closed IAC open. Throttle open IAC closed and if it sticks closed, the next time you let your foot off of the pedal the engine will stall.

Include a flakey ASD and/or fuel pump relays in your list of possibilities. Also, add loose/dirty relay box connections. They can be tightened with a small screwdriver from the top.

8Mud said:

Throttle open IAC closed, throttle closed IAC open. Throttle open IAC closed and if it sticks closed, the next time you let your foot off of the pedal the engine will stall.

Click to expand...

Splitting hairs? Still doesn't cause a problem at cruise. When you let off the throttle you are no longer at cruise.

Did you ever solve this problem. My 96 XJ has had this problem for over two years. It is easy to live with when I don't need the AC but summer in Phoenix I need to shift into neutral when at idle or it will stall. Never throws any codes. I have replaced just about everything including 3 CPS, new distributor and battery, 2 upstream O2, new coil, new three hole injectors, plugs and wires. The cutout at freeway cruise as well as idle has me baffled. I can't seem to get a TPS that fits and runs any better than the original one, I know the 96 is a strange year and some parts just don't fit.

I haven't been on this site for a while, and no longer have my '96 (still have my original, a '92, though), but I went through many of the ailments this thread is full of. The stalling, unintended acceleration, transmission shifting funky, torque converter randomly locking and unlocking. All due to wonky Throttle Position Sensors. It all started after I went to a dealer, and had the recall for the computer re-flash done. I installed new TPSs, and finally went to the boneyard, and purchased a half-dozen TPSs, which were compatible with my early production '96. I cross-referenced the compatibility on Rock Auto, and found that '92 to '96 4.0 units, from ZJ and XJ were the same. I read the values from my '92, a known-good unit, and chose the junkyard piece that most closely matched my good one. Problem solved!

I must warn, however, that the later '96 XJs, most notably the late-issue 'Classic' model, can be different under the hood. Computer, wiring harness plugs, etc. If you've got one of those, maybe concentrate on later units.

My 96 sport is indeed a late 96 ( Oct 96) with 97K miles so it likely has a mixture of 97 parts. Looking at the wiring diagrams all the sensors have the same 12V lead from the computer ( port A4 ) so any that are grounding out will likely throw all of them out of wack. I replaced the fuel pump along with the pressure regulator on the pump and the AC compressor and clutch and even the ECU. The temp is the deciding issue for some reason. I put a 160 thermostat in to keep the temp low and the jeep behaving which works except when it is very not with the AC running and the temp gauge goes up to 210... then the bucking and cutouts begin... turning off the AC at that point does not resolve the issue. I thought of the secondary fan but that turns on whenever the AC is on and until the temp goes high enough no problem. I'm taking it in to a well known local expert shop for a diagnosis... hoping their equipment is more sophisticated than this early ODBII system and my code reader. I was kinda hoping that the problem would either fail hard or go away over the last couple of years but it continues to plague me.