Ford Explorer (Fuel Problem)?

I have a 1994 Ford Explorer Limited that will start on one day, and not the next.
When it starts, it fires without hesitation and runs fine.
No missing, hesitations, or bogging while driving.
A friend listened for the fuel pump prime-up when turning on ignition and heard nothing (on a day it wouldn't start).
Haven't tried this on days it does start, but I was always under impression that a fuel pump is either dead or alive, and hardly ever intermitant.
I examined fuel pump relay and saw no discoloration, but switched with another (abs relay) and will replace both today.
Sprayed some starting fluid on a non-starting day and it wanted to fire, so I'm pretty sure I have spark.
As the tree said to the lumberjack... I'm stumped.

Welcome to the forum!

There's a good chance that the fuel pump is the issue. It's a DC motor, similar to a starter motor. Also similar to a starter motor, it can work one time and not the next. It will often have a tendency to not work as well when it's hot (and after use) than when cold.

-Rod