Hey everyone,
I have a 1998 XJ Sport 4.0 with a AW4. After replacing my destroyed motor mounts i noticed my idle would run high. Soon a CEL popped up. Ran the codes at autozone and came back saying low voltage upstream and downstream O2. Well the jeep is from Maine and has quite a bit of rust. Turns out my exhaust hangers rusted off so I replaced the exhaust from the exhaust manifold back (It had a crack). I also replaced my upstream O2 and then noticed the downstream wiring harness was missing. (PO said he took it through some heavy brush....) I found the wires bare above the T Case. Since then my jeep bogs down when at low speeds (approaching stop signs) and usually switching it to neutral will bring it back to normal. Sometimes I have to stop and restart the jeep to get it to stop bogging down. Also there hare no more CEL and it is backfiring when i accelerate. Highway speeds it does alright but seems to be lacking power. Things done so far are new plugs, wires, rotor cap, TPS, IAC. Any input would be helpful. Thanks.

 

DOC,

hate to say it,,,,,,, cat is probably shot,

or as was case on my ol red resulting in a total rebuild project, head crack.

not the typical 331 head crack, mine was on #2 exhaust port, so it wouldnt keep pressure....resulting in hardly any power on any type of grade....

now look at her!!!!

 

Thats what I originally thought, and since every bracket on the exhaust rusted off i replaced the entire system. I just put a new magnaflow high flow cat on it and nothing. Hmm I'll see what a compression test shows.

 

Well new update I now have CEL. Will see what it reads