Matt21

I have a 96 jeep cherokee classic. while i am driving out of no where it feels as if the exhaust is clogged and the entire jeeps practically shuts down then takes off then bogs down then takes off ect. i have a massive headache from being jerked back and forth . I have replaced the entire exhaust sense my cat was in pieces. (which at first i thought the broken cat was clogging up my exhaust. but the jeep still does it. Now i have already replaced the fuel pump and filter and i cant figure it out please someone help me. I'm lost and about to break out the sledge hammer on my rig.

1976Mustang

Did you actually check the fuel pressure at the injector rail?

ZINGGG

Have you checked for spark? How fast are you driving when it does that? Mine used to do that when I was driving freeway speed (~60 MPH) and I replaced the spark plug wires and BAM, gone.

Matt21

it does it at random i could be going 15 or i could be going 65
i noticed when its wet or cold out it does it but it could be coincidence

tjwalker

Start with tuneup hardware. Fresh Champion plugs gapped to .035, new plug wires, distributor cap, rotor. Yes it could be something else, but you don't want to be chasing your tail for $50 worth of tuneup parts.

Verify fuel pressure at the fuel rail WITH A GAUGE. Anything less is guesswork.

domesticracer1

Mine seems to be having a same/similar problem. I just put a complete tune up on mine today, problem still there. I have'nt checked fuel pressure yet. Seems to have a slight miss at idle too, sometimes worse than others. It usually does it on mine when you first start it up and start driving, it will be fine then just start puttering and almost die. You can let off the gas then give it a little more gas and it takes off fine...

BEETROOT

How about o2 sensors? A bad sensor or fuse will cause similar problems, although usually not as drastic as you describe. And if you banged around on your exhaust at all when you were replacing stuff that could have broken a sensor.

domesticracer1

I checked the fuses under the hood today and found a blown 15amp fuse. Replaced and reset the CEL and the stuttering/ idling wierd. CEL came back and showed code P0138 again. Climbed under jeep to check sensor and only found 1 o2 sensor on the pipe coming down from the engine. Didn't see another sensor on exhaust but found pigtail that looks like its for o2 sensor. Also couldn't find catylatic convertor also.... previous owner may have removed it. Could I tap a o2 sensor bung on exhaust pipe after muffler and install o2 sensor or does it need cat?

Radi

I bet the fuse is blown again. Check the wiring to the O2 sensors very carefully for shorts, abraded insulation, etc.
The rear sensor is there to monitor cat operation. Tapping it into the exhaust without a cat *should* set a CEL (your cat isn't working, lol) although you could try it I suppose.

BEETROOT

You will continue to get that CEL without a cat.

If you really want to remain catless, you might be able to trick the system by installing a rear o2 sensor but keeping it out of the direct stream of exhaust. Basically you drill a hole for the rear o2 then weld washers on the outside of the pipe. Use enough washers that the tip of the sensor isn't inside of the pipe. Thread the washers and screw in your sensor. This way the sensor gets a lower reading and the system is happy.

This is illegal though, and probably more difficult than just adding a cat. You can get a high flow cat at OReilly or Autozone for not a ton of money.

maybe2fast

coolant temp sensor? o2 sensor? need to get into that computer and check out what is failing, it will have a code...should

Matt21

well its not throwing any codes, if i had a faulty fuel injector would it throw a code? also could one faulty fuel injector cause the whole jeep to just throw you back and forth? assuming that the fuel pressure is where its supposed to be. i know that both o2 sensors are throwing codes because it says that the circuit is n/a, but thats been that way sense i got the jeep a long time ago. and i tell you exactly what is is doing just so you guys dont have to keep going back and forth thtrough the pages

The jeep wil drive fine and then out of no where it seems like something gets clogged and the jeep bogs down it never is at idle it idles normally. only when driving it does it most in 1st and 2nd a little in 3rd and i can drive in 6th for a while but eventually it will get so bad that no mater how i play with the throttle it doesnt fix it and i literally have to pull over because it throws me around so badly. when it does happen there is a slamming noise coming from underneath my feet where the pedals are over near the driver side fender almost sounds like someone clucking their tongue but times it by ten times louder. I noticed it has been bad for the past three days when it started raining from the hurricane and does it mre when its wet out, and other times it willl be just fine and normal for a week or two

I list the things that i replaced
tps
iac
crank shaft position sensor
PCM (3 times they all worked fine)
fuel pump
exhaust after cat
entirely rebuilt the engine new head etc
new distributor
new wires and new sparks plugs
so far thats all i can think of off the top of my head.

maybe2fast

o2 sensor (front) is your mixture o2!!! If its got a code it probably needs a front o2 sensor or has burned wires in the harness, trace it!

Matt21

im going replace the fuel regulator, i found out the fuel regulator is on top of the sending unit. I went to a lot of the auto parts stores but all they hav eis the one that goes on the end of the fuel rail. Anyone have the part number for that regulator on top of the sending unit? or can i get the one from autozone and just jimmy rig it in there? its a 96 cherokee classic

Radi

The bad news is if your '96 doesn't have the regulator on the fuel rail, (some did, others did not) it's part of the pump assembly and that part does not appear to be available new. It's a one-year only item. The '96 fuel pump/regulator is Jeep part #4798941.
In 97 they changed it again, moving the regulator outside the pump to the filter assembly on top.