I’ve experienced some wonky O2 sensor issues. (I posted a little over a year ago here) My first hint that the sensors themselves might be an issue was this:
https://static.nhtsa.gov/odi/tsbs/20...60281-9999.pdf
My car was outside the year covered here, but after some good inside scoop from the shop foreman at my Dealer, he shared that these sensors get “fouled” after about 50k on the N63TU and eventually fail.
Super easy to replace. Pull the engine cover, then the air filter boxes and your O2 sensors present themselves very clearly.