I have experienced the same problem from a dead stop at a traffic light a couple of times in the first 5000 miles or so. It felt like the car was going to stall, almost like it was struggling for air.
Tcat,
Relatively easy fix if you have an OBD2 adapter and BimmerCode. Following is a link with a step by step guide on how to fix it:
I have done it on my car and it solved the problem permanently.