1995 Ford Explorer XLT intermittently starting

I have a 1995 Ford Explorer XLT, mileage 117000. In the last month it has not started twice. The first time I left my job in my car, drove to a gas station to fill up, filled up the tank. When trying to start the car, the engine would not fire, but the starter and battery were working fine. Then eventually it miraculously started.
1 month later the same thing happened. I was getting in my car at night to go to work, tried to start, but the engine wouldn't fire.
Had my car towed to the dealership, and my car started just fine for them. They had it for 4 days, did their diagnostics, and never found anything. I've seen some mention of the fuel pump in these threads, but wouldn't the dealership have looked at that? I've had to buy a new car because the 1995 Explorer is now unreliable, but I'd like to get it fixed to sell.