Originally Posted by Josh@STILLEN

Actually Jesse, Berk is dead on when it comes to the function of the secondary O2 sensors based upon my conversation with my R&D guys today on a different application that rolled into this discussion.

My understanding (and I'm in marketing, but privy to a lot of the tech going on) in regards to these sensors (including their function on previous Z's and the G35/G37s) is their drivability control, the secondary fuel trim function, when you're not under hard throttle situations where pre-loaded maps take function. Idle, cruising, CELs can be affected.

I'm not going to comment on your knowledge, obviously I would have no idea, but in regards to this car, engine, and applications, I wouldn't be so quick to discredit some of the people posting on this forum..