The Z developed a rattle in the exhaust a week ago and I figured it was a loose heat shield- until yesterday when the service engine soon light came on. I took it in today for service and as suspected the O2 sensor had come loose to the point it was rattling and sucking air in. I had TPs installed a couple weeks back at a speed shop and apparently they didn't tighten the O2s down enough. The dealer was nice enough to not charge me for the non warranty "repair" and cleared the code for me. CEL code was P2A00 according to the invoice.
While I was waiting I stopped by the part's counter and asked if I could buy a Nissan branded bathroom sign. He looked at me like I was crazy (which I am, granted) so I pointed out his restroom sign. He just shook his head...
Nismo drivers I swear!
On another unrelated note I visited the attached Infinity dealer and scoped out the new M56X with the aero kit. After having driven the QX56 for business many times I can tell that car must be a ton of fun.