ok.. heres my problem.. when i start up and leave idle or if i start up and drive the motor wants to cut out and bogg down/cut out at the exact place and time...(approx 3mins of idle or 1/4 mile of driving) if i give it full throttle it clears up and im good to go..

it happens from a cold start or if i drive and leave it shut off for 20 mins or more..

now i just had my exhaust reolaced,cat back, and now i have this problem.. never had any issues prior to new exhaust

i have no check engine light either...

thanks for any input....

 

any help???

 

im having the same issue. ive replaced down stream o2 sensor and tps. i just cleaned the IAC and nothings changed. Maybe its the upstream o2 sensor?

oddly i have my check engine light on and when i try to hook up a scan tool the computer wont communicate with the scanner. this is really annoying.

 

turns out that this common problem can be fixed by simply unplugging the UPstream o2 sensor and cleaning the connector. mine was stuffed with mud from one of my latest adventures. I disconnected it lastnight and took it for a troubleshooting spin and it showed no signs of the stumbling stuttering falling on its face issue. when i disconnected it i realized how dirty it was and figured it would be best to clean it and plug it in again to see if that was the cause. it was. So if you clean yours hook it up and reset the computer and still have this problem I would bet your issue is a faulty upstream o2 sensor. good luck hope this helps and keep us posted.

 

damnt... now i am curious about mine. hthe kid i bought the jeep from went bogging with it right before he posted it online. lol that might have been my problem all along...

 

clean it up. it takes 2 minutes if you have a flashlight and something to clean it with. i used the throttle body cleaner cause its what i had. break cleaner would work or the specific to cleaning electrical connectors. jeeperscreeper92 do you still have the issue?

 

lol yes. i first thought it was vacuum leaks;. i know i have huge ones. that i been slowly finidning and pluggging.
but i melted my piston rings the weekend of the 12th. so i havent started it up since then. it still has a rough idle. it cut out on me when the rings first melted. right between two lanes after a right turn at the bottom of a hill...

 

i use break cleaner to find vac leaks. or the universal indicator on these which is only the defrost setting working when you set it to the other settings. mine is missing the vac canister cause the front end was messed up bad on mine.

 

jeepers how are you sure your rings are shot? Just curious

 

had a friend diagnose it for me. when it cut out on me. my friends (she was a chick i known for like 10 years... lol if only she hadnt wanted starbucks so bad ahaha) any how. she called her brother(fellow XJ owner whos modded four of them and helped me out of a couple of binds) who came down and started it up. black plume of death shot out the exhaust. **** all over the pavement. he ran a compression test results were all over the place. he confirmed my jeep was roast. good as gone. he went over the problem with me and said if i can check out my piston rings. if they are broken or melted then thats my issue. right now i only need it to get me around town/. back then i needed it to make ONE last drive on the highway to get me home. he confirmed my doubts. told me theres no way it would get home. even on backroads. I had to leave it behind a Arco for a night so i could find a place to crash in town and come back to get it towed. i know engines. but my specialty lys in brakes and suspension/steering. i pulled the pan theres flakes of ring metal all in the oil.

 

that sucks. best just pulling it and puttin in a new one. good luck.

 

eh yeah i found one for 240. but it will only cost me like 120 to replace the piston rings. all i need it for is to get around town again.

 

the question is how bad are your cylinders scoured only taking the head off will tell. or if you have a nice mechanics camera you can peak through the plug holes.

 

Nah no camera. but yeah i plan on removing the head saturday. anyways. srry for hijackin the thread.

 

Thanks guys. I feel my problem is an o2 sensor. I will try cleaning and or replacing and let you know...