A couple of months ago I posted a query regarding a significant stuttering and stumbling on cold starts in my 2012 with 75,000 miles. Of course, the check engine light was on constantly. It was pretty much a consensus that it was carbon build-up on the intake valves...which seemed to make sense from many's experience. The problem wasn't too inconvenient and I kept putting off scheduling a service appointment. Then a couple of weeks ago my (original) battery died and I replaced. Upon starting, the OBC was going crazy, showing all sorts of error symbols, front windows wouldn't roll down but rear would, turn signals wouldn't work, etc. Finally, I scheduled a service appointment.

It took them a week but this was the diagnosis: Stutter and stumbling on the cold start was due to a bad high pressure fuel pump (my second). And the "crazy computer/car" was due to a bad FRM. The good/great news was that all was repaired at no cost - MINI has extended the warranty on both! Walked out the door for a grand total of $0!

 

Glad it worked out well. No walnut blasting for you!