On the way to be checked out, it stalled. It had symptoms of being flooded, but didn't blow black smoke or stink of fuel.
This chart shows, and its caption contains, the maintenance schedule for most trucks like this one. I don't know which items are up-to-date.

A
PCV valve is ~$8.
Serpentine Belt is a top-quality
Dayco PolyRib 5060990 (MotorCraft JK6995A or JK6993) in good condition.
Detailed inspection $120 DONE