Yeah, I've had a DC JDM 4-1, highflow CATCO 2.5" cat, and 2.5" custom piping on for over 3 months now, with NO problems. Then all of a sudden this week, CEL 67 pops up. Do you guys think it's the cat, or the O2 sensors? Should I try a Carsound cat instead, or take it to the dealer and complain about the O2 sensors?

Help!!!

 

It's definitely the cat. Code 67 is cat malfunction. A couple of days after installing my carsound cat I got the same code. I put my stock one back on and it's been fine ever since. When I change my ecu I'll throw it back on.