Car stalls in park & driving sometimes. Starts up again after it sits for a bit on 1999 Ford Taurus

This has happened 3 times in the past few months. The first time - it stalled when I put it in park in the driveway after driving it to and from and appt.
The second time - it stalled while I was driving it slowly in a parking lot.
The third time - it wouldn't start again right away shortly after I parked the car.
Each time - I let the car sit for around 30 minutes and it started right up again.
Mechanics ran diagnostic on it, and tested fuel pressure, and both came out fine.

Asked by for the 1999 Ford Taurus
check pressure when stalled