I have a 2000 Ford Explorer XLT. Traveling at high speeds after an hour in 110 degree weather causes the car to stall momentarily. If I continue operation the vehicle eventually shuts down all together. All gauges read normal after shut down.

If I let the car cool down for about 20 minutes, it will start up again. Lowering the speed from 80 to 55 allows me to drive a lot further but the problem still persists.
What should I do?

Christian