2005 Cooper S with 80k miles.
So doing the research here I think this is the Harmonic Balancer or Crank pulley. Maybe one of the other pulleys, as a few others have noted the P1688 fault along with the car stumbling, going into limp mode then having a slight oil smell. Being caused by the pulley. Thing is I am also getting a P0304 which bothers me a little, though it is a pending code so it may just have been caused at the moment of failure of the pulley. So anyone have some suggestions?
I will get it up on the jack and pull the right side apart soon so I can check the pulleys visually but before I do any other thoughts would be helpful.

The one last note is that I have had a very slight noise that sounded like a possible pulled bearing for the last year but it seemed very subtle so I left it alone.

thanks