OMG!!! I just had this happen to me for the first time yesterday afternoon!!! I was stopped at a red light, and when I began to accelerate the engine seemed to stutter a bit...It was similar to a misfire, and I thought for a second the car was going to stall on me...The temps here in my area were barely in the low 30's yesterday, and were probably the coldest my 5 has seen I've purchased it...It did this again and again until we were driving about a half hour or so and then suddenly the issue disappeared...
A quick trip into the service department today revealed nothing wrong at all and the tech was unable to duplicate the issue...Oh, and the temp is about 40 degrees with rain today...I was sent home with the newfound knowledge that these cars can sometimes exhibit this behavior before the engine warms up to what the tech said was "optimum performance levels"...
I hate to sound high and mighty on this one, but with the technology we have today, I can't accept a brand new car having issues in cold temps like this...I need the car that my family depends on everyday to perform consistantly and safely...