I have an '07 S, 4700 miles. Started the car after work, got the yellow engine warning light. I drove the car home, but could barely make 30 mph. No power, and the engine surged up and down all the (thankfully short) way home. Once I parked, I shut off the car, restarted it, and the problem went away. Ambient temps were in the low 2's. Any clues to what might have happened?

 

I just had the same problem. Temp was about -25 Celsius and very windy and blowing snow. Car was fine that day. Next day I started it and it sounded awful. RPMs go up and down, black smoke out exhaust. Mini is a new 07 Cooper S. Was able to drive it to dealership -no appreciable power loss when driver. Apparenly moisture got into the intake. Dealership said that had some similar problems. They cleaned intake and lubricated part of throttle I thought they said. Hopefully that won't happen again as it get quite cold here in the winter.