Try turning the wheel to left in the driveway at idle. does it stall then? If not the IAC is not the problem. If you cant reproduce it sitting still, it would seem to point towards inertia. That means fuel pickup in my mind. Did you try filling it up? that was a good suggestion too. Maybe inertia switch in the trunk, thats another thing you could bypass and rule out. I have seen them act up in fords. It has a reset button and is supposed to cut fuel pump power in an accident. Check your manual for location, you can bypass it with some wire and terminals stuck in the connector. Replace it if its bad, dont leave it that way.