spoole96
Well-Known Member
- Thread starter
- #1
I installed some kooks LT headers with high flow cats and now i get a P0420 Ford - Catalyst System Efficiency Below Threshold Bank 1 code show up every once in a while. From what I've read so far, it's probably the rear o2 sensors causing the trouble code since they are calibrated for the stock catalytic converters. Should I work with the tuner to turn off this code from coming back anymore and causing the check engine light to come on? Or, I read you can install some spacers on the o2 sensors that will get rid of this problem? What's the best thing to do?
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