I've had what I'd call a near stall/backfire occur 2 days in a row after coming out of work on my MCS with 600 miles on the odometer. I push the start button and it seems OK, then starts to stumble and almost stall, but does not. It only happens after sitting in the lot at work all day. Has never happened in the morning or after running short errands. I've put gas in the car twice now, both times BP 93 at about the 1/2 empty mark. My first thought was bad gas, but I don't think so and I even switched BP stations just in case. Any thoughts on this...software update, fuel pump, etc. Car runs fine otherwise, but this worries me on a brand new car. Already considering the extended warranty if I keep the car after the original warranty period. Thanks.

 

Could be the early signs of a faulty high pressure fuel pump. I had those symptoms shortly before mine went out on me in my '07 R56 MCS. I would hope they have the high pressure fuel pump issue fixed on the '11s but who knows.

 

I can't imagine them putting in a bad HPFP design back into new cars, when they know it was a problem on the BMW's AND MINIs. BUT THEN AGAIN...
my father just picked up a new '11 X3 35i, and when I went to visit he told me to take it for a few days to test it out. Well, a day later a passenger got into the passenger seat and I got a SRS warning, upon looking it up, faulty air bag sensors in the seats were recalled on earlier model year BMW's ~05-08, and this seemed to be the exact same problem, even though this was a '11 with only 900 miles on it. SO, you really NEVER know.

 

Sounds very familiar . . .

https://www.northamericanmotoring.co...-start-up.html

 

probably HPFP, my 2007 had the same problem and is getting that pump replaced now. hoped they would have changed this faulty pump, but.... guess not.