With a P0420 code. I removed my cat system and saw that one of the precat honeycomb was missing. Since everything seemed okay I ordered a new eastern cat system (20379) off rock auto put everything back together and kept driving.
Well eventually on my way back from Moab on the I-70 I lost power and couldn't go over 50mph. It continued to get worse because the exhaust was clogged. So after some gracious jeepers got our Jeep home I removed the exhaust and made this little video to show what I found. Hopefully it helps
*disregard the welds on the pipe near the flange I was setting the welder for the new cat system.