Engine is stalling one day and wont start the next

Next time it refuses to start don't wait for it to make up its mind-do below immediately to determine if its fuel or spark problem

https://www.2carpros.com/articles/car-cranks-but-wont-start

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if okay-check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,coil's resistances,cap and rotor,distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it and keep testing

Intermittent most difficult to diagnose need to determine what is lost fuel or spark. Next time wont start check for spark at plugs if good then spray carb cleaner in intake if it fires then fuel delivery problem