2000 Saturn LW1 won't start... periodically

My car will, periodically, not start. It cranks vigorously, but won’t catch. If I wait 10-15 minutes it will fire right up.

Car has 113,000 miles on it. Just had a major tune up session - new plugs, wires, filters, fluids, and the problem is still there. (It has been happening for a few years, every 6 months or so. Lately it has been much more frequent.)

Battery is strong. As I said, new plugs and wires recently. New fuel filter. Fuel pump hums for a couple of seconds when I turn the key (and doing this a couple of times when the problem occurs does not resolve the problem).

Somebody in another discussion mentioned a fuel pressure regulator… maybe it’s allowing too much fuel to the engine? How can I test that?

Otherwise…Vacuum hose(s) leaking? Bad injectors? Something else?

If you hold the gas pedal to the floor, will it start? If so, it’s flooded with too much gas.

I will try that next time the problem occurs. I didn’t realize that doing that would actually clear the fuel from the cylinders, so that should indeed be a good test of the theory - I’ll let you know!