emissions

Hey! I made this post to hopefully help out another single turbo n54 owner looking to pass emissions. Information on my car - 2007 335i N54 On3 single turbo kit Manzo catback exhaust E60 mix on a custom tune (jb4 + mhd bef) I am in Colorado, typically for a 2007 they would do the test on the...

No idea what the hell is causing this anymore. The codes were involving both post-cat o2 sensors and pre-cat o2 sensors with lamba/mixture errors. I replaced both back o2 sensors and the front o2 sensor that was giving codes, they still appeared. At this point I assumed it had to do with my car...