Not starting on cold mornings is a classic sign of a worn-out fuel pump (I know, I've replaced 6 or 7 of them on various Explorers over the years and a worn fuel pump was the problem 99% of the time). I've found that the fuel pumps typically start giving cold-start issues at around 175k-200k miles. When it's colder out the fuel pump's motor brushes retract slightly and don't make a good contact on the motor's armature. Sometimes thumping the fuel tank below the fuel pump, or repeatedly toggling the ignition key on/off will get the pump started again and it may work fine for a time but typically it will not run on a cold morning. I had one that would fail randomly on hot days maybe once a year. This went on for multiple years until it finely failed hard on a cold morning. Replaced the pump and have never had another problem. I only recommend Bosch brand replacement fuel pumps.
Tip: If your engine isn't starting don't just keep cranking it until you run the battery down. You'll just ruin your starter motor. Check your fuel pressure at the fuel rail with a gauge the next time your engine won't start. You should be seeing around 60-65 PSI of fuel pressure. If you don't the problem is fuel pump related.
In my experience other (1% if the time) no-start fuel related issues might be:
A tripped inertia fuel pump switch
A bad fuel pump relay
A severely clogged fuel filter
An issue with the crank position sensor or cam position sensor
