I should mention that I did my replace because jumped timing led to my injectors firing twice for each cycle. It would barely run like that. I had 7 psi exhaust pressure they were so carboned up by the time I figured out what was going on. The internet cleaning methods did not work at all so I had to replace.

You can always hollow out the old cat, and run with it, no ill effects on drivability. save the new cat for test time. wink wink.

Thanks for all the input everybody. @BlueRidgeMark , I appreciate all the info, especially the referral to that sticky by that ugly dumb bastard.

My first step is going to be to try the spark plug non-fouler and see if I get lucky. If the Jeep stops spending my money the way it has been to bring it back to health, I'll look at the CATs in another year. The USPS maintenance allowance only goes so far, and I've done a tranny rebuild AND engine replacement in the last 12 months.....so yeah.

Thanks again people! I will update with my results when I get to it.....might not be until September.

Well, not to be "that guy" but here goes. It's a violation of Federal law to tamper with the emissions system on a vehicle used on public roads. Oregon State law has similar prohibitions. This includes removing, gutting the cat, tricking the PCM. (IANAL)

Are you in a DEQ zone?

Since you're either a Federal employee or contractor, I thought you should know.

Yeah, I'm aware, and I appreciate what you are saying. I am not in a DEQ zone. Luckily for me, I live and work in such a rural area that we rarely see cops, and the postal service can barely put its shoes on in the morning much less do vehicle inspections on POV routes.

Are you suggesting I travel back in time 5 years and not buy new cats? Or just that I should break the law. Either way, not going to do it.