My 2008 mini with 44,000 miles on it is not fun to drive any more! It was running really rough and the dealer change the spark plugs. When I got the car back it is now sluggishly unresponsive, can't make a quick start from stop on a ramp on when stopped at a stop sign etc., and when I brake the car lurches forward a bit, the RPM s go up just a little, it is a power surge . And the car has stalled out twice in the last month. The dealer told me I had bad gas, I don't warm the car up enough and that the engine needs to discharge upon stopping thus the surge. Funny, I never had these problems before and of course when the service manager drives the car it doesn t display any of these problems. I hate to drive it now. What do I do?