My 2005 Buick Century with 353k miles gets a recurring P0420 code, catalytic converter operating below efficiency level. Twice this year, I tried using Cataclean, but with no success. I noticed a small hole in my muffler at the seam. Could a lack of exhaust back pressure cause the CC to operate inefficiently or improperly? Can anyone recommend a catalytic converter cleaner? Or, is it all snake oil?
난이도 보통⏱ 60~120분리프트특수공구