2001 Ford Ranger cranks, but not start

My 2001 Ranger is used for work to move furniture multiple times in a day. 7 weeks ago, I had moved a dryer w/ it, drove across town for a meeting, got back in & it refused to start & run. The same thing happened 3 days ago on a longer, fuller route w/ a trailer attached. Both times, the truck started & drove home ok AFTER sitting off waiting for my emergency ride. While I waited, I looked up the issue in the owners manual which told me to depress the gas pedal 1/3 to 1/2 & then turn the key in ignition. The first attempt did not work, so I repeated the steps, which started the truck & I was able to drive back.
Both times, the truck started no problem the next workday. What advise is out there to work with this?
Does this sound like a problem worth fixing (for the age of the truck vs. cost of repair)? It has pull some weight, including on trailer, in between the two occasions.

To see if the trouble is with the fuel or ignition systems try spraying a small amount of starter fluid into the intake the next time this happens. If the engine fires right up you will know that the fuel system has a problem.