If you're getting inefficient cat codes, put spark plug non-foulers on the down-stream O2 sensors: They work. Fix what caused the problem in the first place (in my case it was replacing bad valve stem seals on the 2.7), and then put the non-foulers on - no more code.
http://www.dodgeintrepid.net/showthread.php?t=101141
http://forums.clubrsx.com/showthread.php?t=296791
Omg it stinks!
Linear Mode
