1997 Ford Taurus turns over, but won't start

but other times it turns over, but won't start. Next time it refuses to start do below and tell me what's missing fuel or spark

Get a carb cleaner and spray into the carb or the throttle body on an EFI. Did it start and die? If not disconnect a sparkplug wire or 2 and ground it to the engine -have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel problem, check the fuel pressure to rule out the 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,distributor pick-up coil, ignition control module, cam and crank sensors-