cjxjman

I'm at my wits end.... Here is the problem. When driving, it feels like the iginition is misfireing, then it will cut off. The motor will surge and die surge then die. If you floor it.... It runs PERFECT! Ive tested the TPS and it shows good BUT will be replaced due to age and 180k on the motor.

BACKROUND: Had a bad exuast manifold. Removed and had welded back together. Reassambaled with this NEW problem.

Ive checked wires, connections, bolts and still have the same problem.

Also as a side note ive found a "new" knock/tick from the distributor. Not loud but there.

Any ideas before I use my firefighter training on it?

BuckB91XJ

Well, if this problem started after the exhaust manifold was weldedup. The only thing i can think of that is close to that is your O2 sensor. Maybe it was damaged while you had the crack in the exhaust manifold from getting hot and cold all the time.

smitysjeep4x4

try 02 sensors thats what was happening to mine i would have to keep my foot on the gas and break while stop becuse it would surge then die try just unpluging it to start. youll get a engine code cuz you unpluged it but. if the surgeing dosnt accure than thats your problem that fixed mine and check your battery too that could affect like that cuz i had to replace mine cuz of that thought.

That Jeep Guy XJMJ

check your cank position sensor also, i recently replaced my exhaust manifold and found that one of the wires had a split....
also check the harness to your Fuel injectors, and inspect the wires for the same thing

cjxjman

Ok checked all the wires. they seem ok. no cracks or blisters. No corrosion. All the Fuel Injection wires are tight and in good order.

computer spits out 12 (understandable i just had it out) 21 and 21. Im guessing for the two O2 sensors that are there. Well kinda.....

The first sensor near the ex. manifold is there. but the one down by the cat hasnt been there for like 8 years....

I unpluged the O2 sensor that is still there. Engine runs. not sure on the problem tho ( im at work cant hit the open road till morning )

If I have the same problem it COULD be the O2 sensor but also something else..... if im thinking right. Could a vac leak when the motor gets hot, making the intake/ext manifolds "warp" do it? Also would a bad distributor do this? I found that I can move shaft inside the dis cap side to side about 1/16 to 1/8 inch, not good I dont think.

How do I test the other sensors in/near the throttle body? (I got the TPS sensor already)

on a side note.... I MISS MY OLD CJ! soooo much easier to work on!

cjxjman

Ok unpluged O2 sensor. Runs ok. Seems to be less perky but that's ok. Next step replace sensor and Distributor.

CherokeeGP

Def. sounds like Oxygen sensor. I just replaced my cracked headers and the same thing happened to me. A couple days later the Check Engine light came on and it was the Upstream O2 sensor. Replaced it and it runs great. Instead of just unplugging it, I would reccommend actually getting a new O2 sensor and putting it in. The o2 sensor sends codes to the cpu to adjust fuel delivery.
If you change it yourself, run the engine for a couple min. to heat up exhaust pipe/sensor & it will be easier to unscrew..

cjxjman

Yup Plan on the O2 sensor now and the Distrub. It has a hell of a noise now. I think the guts are worn out.

Michigan Jeeper

On my YJ i had this problem. I couldn't even get the motor to run without holding the gas down. Check the EGR valve; i just unplugged mine and it worked perfect. Good luck