[jeepcreep21]

I have been through a wide variety of post in Jeepforum.com but still can not find exactly what I am looking for. I will try to keep this as short as possible but I am trying to solve a problem that comes and goes with my 97 TJ 2.5 4 cylinder.

Problem:
On occassions, my Jeep will sputter and/or backfire a bit. Sometimes its bad. Sometime its not. And on somedays, it never happens.

I will try to detail the most common occassions!

#1 Leaving work, highway driving, 10 miles down the road at a constant 55 mph. All of a sudden, my rpms drop and you can hear what I think is a build up in the exhaust or similar to a backfire but very muffled. I can punch the gas pedal to get back up to speed but the moment I let off the throttle just a hair, it wants to do it again. After a few miles or when I come to the light to cross the bridge into town, it eventually goes away and resumes normal behavior.

#2 Idling in the driveway, using compressor to charge air tank, 5-6 minutes into the project at idle, it starts to sputter almost to the point it wants to die. There is a funny odor. I cant tell if its a sulpher smell or carbon like smell. Again, I can hit the gas pedal and let off againand it will do this for awhile and eventually go away.

#3 This is the least often though. I start my Jeep, it idles fine, and back out of the driveway. I go aprox. 50 ft to climb a small hilland it sputters while climbing. As I aproch the downside of the hill, it goes away. Right before I get to work, occasion #1 occurs again.

I can go weeks without this happening at all but I also go days when its a common occurance. Please help me if anyone has an idea of what may be possible. I am on my second engine but this also hapeened on the other 2.5L as well.

[67jeepstang]

wow. sounds like an emissions problem. maybe your EGR valve is plugged.

[jeepcreep21]

I keep reading about O2 sensors and still wondering if this sounds like the problem or if I have a Cat problem? I also have someone telling me that the stock mufflers are filled with many little orifices and could be severly clogged. It has seen its share of mudholes but the mud tore up too many parts. Now i prefer to crawl and climb with an occasional mud hole.(lol)

[Konig55]

Back in 1999. I even puttered out on the interstate in downtown Atlanta during rush hour. It was the O2 sensor. I had it replaced and haven't had the same problem since.