1998 XJ, 4.0L, Auto. My cat started to rattle from the inside, but not sure to replace it or just remove it. I've done a search on this site and couldn't find any info. My emmissions inspection (Aircare) is good till Feb 2015. After Dec 2014 light vehicles are nolonger required to do Aircare.

Will the motor run poorly without the cat?
Do the rear 02 sensor readings cause adjustments to fuel/air mixture or can I just cover and mount it somewhere on the body to prevent an error code? I ran the jeep for a year with a dead sensor and didn't see any difference in performance or fuel economy.

I'm fine with just replacing the cat, but if I don't need it why bother...

Thanks folks.
forgive me for being a newbie in this site.

Nez.

 

It's a federal offense to remove the cat. If the rattle is not too loud just turn up the radio. If you decide to replace it, shop around as prices vary considerably. The downstream o2 sensor monitors the cat's performance so if you remove it you will probably end up with a check engine light and and even worse fuel consumption (can you imagine that).

 

+1 to everything oldfart said. Order a high-flow cat from the states, direct fit with an O2 bung. It is definitely illegal to run without a cat (and REALLY not nice to breathe!). OBD-II Jeeps use both of the O2 sensors in determining fuel mixture.

 

Thanks guys. I'll find an aftermarket high flow unit.