An update on this. My car has been at the dealer for three weeks and it is still not fixed. The dealer replaced GEM module, but it has not fixed anything. The dealer says on record that the car is "not safe to drive, as it can stall at any time". They say they replicated the problem, send some data to Detroit, then Ford asked them for some additional data, and this back and forth goes on for two weeks. Very frustrating experience :(