I have had a DC 4-1 JDM header, CATCO 2.5" highflow cat, and 2.5" custom cat back piping for about 3 months now without any problems. Now, all of a sudden, I'm getting the check engine light with code 67.

I check my O2 sensor and they're plugged in tightly, one into the header before the cat, and one into the piping after the cat. So why am I getting the code 67, and is it affecting my performance?

Any help is greatly appreciated! Thanks guys.

 

The book says, Catalyst System Efficiency below threshold. Could be the catalytic converter or the rear 02...


Jason