Dreaded P0420 code. 08 G35 Sedan with 113000 miles. Inspected cats and o2 sensors, no issues noted. No vacuum leaks found. Wife has noted an increased sulfur odor from exhaust, particularly while idle. No exh leaks noted. I will check O2 sensor voltage data when I get time, but looks like cats are in need of replacement. Thinking about either Davico OEM replacement cat or upgrading to Berk/Stillen HFC's. This is my wifes car so she is not too interested in improving exhaust sounds. Any suggestions?

 

If you're looking for a stealth replacement, I would recommend just OEM style. I believe a HFC would introduce more sound and will definitely be more expensive.

 

Hi Janda930, did you install the Davico OEM Cats? If so how are they working out for you? I'm thinking on purchasing a set.