Strange idle symptoms and a foul exhaust smell

[BlackMJ90]

So for a month or two my MJ has been having some strange symptoms. When I first start and drive it and come to my first stop light the truck begins to bog a bit and the suddenly return to normal idle so abruptly that you can feel the car lurch forward a little through your foot on the brake pedal (it’s an automatic). After a little while longer the exhaust begins to emit a foul smell that is notable from the cab with the windows down. Anyone have any good ideas?

[87MJTIM]

Is your Cat going bad?  A blocked exhaust system will cause similar symptoms with the engine.  A bad cat will emit a funky smell (so I've heard, never experienced).

 

BTW - fill in your signature with details on your MJ: Yr, engine, trans, 2 or 4 wd, any modifications done to it.

[BlackMJ90]

Hey thanks for the reply. I was thinking it could be the cat but wanted to see if it could be anything else first. Sorry but I am fairly new. How do I fill in my signature?

[Pete M]

 

[BlackMJ90]

Thanks for that! Should be included from now on

[HOrnbrod]

17 minutes ago, BlackMJ90 said:

Thanks for that! Should be included from now on

 

[cruiser54]

First off, check the line from the throttle body to MAP sensor. Any leaking vacuum there and the MAP tells the ECU to add fuel.

 

Also, go to www.cruiser54.com and complete tips 1 through 5 before anything else. 

 

 

 

 

[Eagle]

When did you last replace the oxygen sensor?