Got a check engine which disappeared when i turned car off and on and is not easily reproduced but does come back about every 30 miles on its own. Code P0087 which my OBD 2 reader says is fuel system. Does NOT happen under hard acceleration or anything perticuler I could discern. Any ideas? Will take it into mini dealer if i cant figure it out. 2011 R56 Cooper S

 

Probably High Pressure Fuel Pump is starting to fail. 2011 cars seem to be covered under an extended service bulletin. In my case they threatened to charge $99 to diagnose, but wiped that off and I paid zero for a replacement on a 2011 N18 engine.
Good luck.

 

I replaced gas cap and it seems to have fixed the issue. Im going to get it checked out anyway but so far so good.

 

Yep light went back on last friday, I had an appt in advance at mini dealer. Took it in and they confirmed it was HPFP pump as you suggested. They are replacing it for free today. Thanks again!