My 07 350z VQ35HR is throwing CEL p0420 with stock exhaust and catalytic converters. I've tried resetting it multiple times, but it comes back after a few days or weeks. Should I try replacing the bank 1 o2 sensors, or get a set of Kinetix High Flow Cats? Stock Cats are too expensive to replace.

Thanks for the help
-Trent

 

If I recall correctly one or both of the cats are going bad. I had the same code when I installed my test pipes so the code should relate with stock cat. How many miles?

 

85,000 miles.

Should I go with Stock Cats or Kinetix HFC? Gonna sell the car soon.

 

80,000 is when mine went bad.

HFC or test pipes will only benefit you with supporting mods. My guess is... it's highly likely you will still get the CEL light with either mods. Don't believe in what website say or what other members say because it's a hit or miss situation, every car is different.

Getting your car tuned and deleting the cat code is the only solution, however, I can be wrong though.

GL