off to a rough start!

Yes they did. Not positive on years though. I want to say  from 2000 to 2006.

I guess this was their solution to so many cracked manifolds...
 

 
Yea but back on topic, what are the new trouble codes?

Attached Image(s)

http://lgcdn.jeep4x4center.com/media/catalog/product/cache/1/image/270x/9df78eab33525d08d6e5fb8d27136e95/f/r/front-exhaust-pipe-17613.22.jpg

and this is the head pipe.
There is also another cat at the end of this mess.
Not trying to get up on anyone, just know because I have been there.  The head pipe was replaced once during warranty and the head pipe and O2 sensors replaced by me once on my dime.
 
What are codes telling you?

Could it maybe be his head pipe then? A clogged cat? Those cats are tiny, seem like theyd be plugged easy, especially if the plugs were fouled, theyd be burning dirty, and a plugged cat would cause an engine to bog and lose throttle response.

I know for sure that the 2001 model has 2 upstream O2 sensors only. It was an attemept to control the exhaust gasses better as emissions was tightened. Again they split the manifold system in half to control 3 cylinders each.

Uh...yeah I cut my cat off with a sawzall in March at Shiloh because it was rattle ling inside . I did replace my headers and they were beyond cracked.