Yes you have O2 sensors on the inlet and outlet sides of the cat.
Well... that depends on the year/engine.... I have 3 cats on my 04 I6. the two on the down pipe have O2's upstream and downstream, totaling 4.... the cat just before the muffler doesn't have any sensors at all.
If your smog Nazi's do a visual on your Jeep and find the CAT isn't there, they could turn you in for tampering... its all about the law.....
~Todd~ 2004 X 4.0 5 speed---SOLD
4" Lift, 4.56's, 33" Duratracs on M/T Classics
RR SYE, Tatton CV, MML, BL, TT, Dynomax Exhaust
Hella Lighting: Driving, Fogs and H4 E-Codes NOPE! ... and NEVER will be...
The ecu will throw a code unless you either modify the program or run something like an MEL eliminator in line. Re moving the cat can lower your low end torque on some engines. If your cat is just bad, I have had excellent luck with the Magnaflow cats. I use a 16" Magnaflow on my emissions pipe for street car. The car gets a 10/192 limit in the HC emission, with a small block Ford .577" lift cam and a 112 deg lobe seperation.
My 06 dosent have a sensor before or after the third cat. That being said, i replaced mine wed. because of a dent i had put in the stock one. Magnaflow High-flow cat 45 bucks on ebay. Part number was 94105 iirc.
I'm frustrated with my inability to understand what is and isn't a "high-flow" cat from magnaflow. I can only assume that the ones sold as "off-road only" are high-flow and all others are not high-flow. Am I thinking correctly or am I missing something?
Don't worry about high-flow cats, it won't make any difference. Besides, your engine was designed to work into some backpressure which from what I have read helps improve low-end torque.
Good to know. So is it safe to assume that if I just find a dimensionally comparable match for the stock cat and have it welded in place I should be good to go? Is there a magnaflow replacement that has the o2 bung already in it or will I need to have one welded in behind the cat as an extra step?