2015 ford escape loses power at high altitude

The air is pretty thin at 4000 feet but engines are designed to adjust the fuel accordingly I am told. So maybe it's a fuel problem. Have the fuel filter changed if it's more than 30K miles old. I would not suspect the fuel pump but a fuel pressure test could be done. Or you can wait until you come down out of the higher elevations and see if thin air was the problem, if the power comes back.

I have 144000 miles on the car and have never had fuel filter changed. This happened last year driving in Salt Lake City. Took the car to a ford dealership and it showed no codes. Kept the the fuel above 1/2 a tank and was able to drive home to Missouri. Never happened again until now coming to Denver.

4,000 feet is nothing. 10,000 feet I could see a noticeable difference happening. Was the power reduced or the engine died?

If the fuel level in the gas tank is the key then perhaps the fuel pump of the fuel pickup is the issue.

I wasn't aware you have gone 144,000 miles on the same fuel filter. The recommended service interval is 30K miles. There's your problem...you're five filters past due. Miracle the fuel pump can push anything up to the engine. If the filter ruptures, you'll have a mess at the injectors.