My car sometimes doesn’t start. Mostly after it’s up to temperature. It cranks and cranks and cranks but doesn’t turn over. As soon as a call a tow truck, it starts right up.
Maybe crankshaft position sensor, maybe fuel pump, maybe an ignition relay underhood. All can cause an intermittent no-start because of temperature. It needs to be tested for fuel pressure and spark and power to the ignition when this happens. Maybe a trip to the mechanic will trigger the no-start?
The relay and sensor are both cheap and I’d just replace them anyway on a 19 year old car. If the car has over 130K miles or so and never had a pump replaced, I’d do that too, whatever you find.