Stumbling at 2000 RPM's and whistling? noise on acceleration
 

I just purchased a 2012 Mini and at around 1500-2000 RPM's (Sport or Regular) it will start to lose power and lurch. I can stomp it and it will shift down and accelerate. I also hear a whistling? noise as the engine rpm's increase. It doesn't happen all the time, mostly after its warm but it is getting more frequent. Engine light came on once, probably cause I stomped on the gas in frustration, but went away when I stopped and re-started the engine. Engine seems to run great sitting still, only happens when moving. Any ideas?