Usually you get 3 posts to convey 1 message, this time it is one word for some reason....
The last time(s) my 5.4L 2001 stalled in those conditions it was a dirty IAC piston.
If you remove the IAC and clean the inside of the piston it should stop.
- Could be an actual problem with the IAC, but best to start with a quick cleaning.
I cleaned mine 2 times and then replaced it just as a maint cycle item. Dad still has not had a problem with it stalling ( he has it now for a work truck ).
Here is the piston inside the IAC that gets gummed up.