My 92 saturn does'nt always start. sometimes I

Because starting (as well as most other items) are/is controlled by your computer system which depends upon sensors in order to work properly, diagnosis online becomes a guessing game. I suggest you have a code test done (most larger parts stores do this free) If you have any faults stored it may give you an idea where to look. If not, do individual component tests as outlined in haynes, chilton, or any other basic manual you have available. Pay close attention to readings from the crank sensor, and cam sensor. I would compare readings both when the car is starting and when it's not. Also, you could have a problem with the chip in the ignition lock or a loose wire or slight deterioration inside a harness connector (often does not look like battery corrosion but more like a darkening of a pin) sensors are low voltage items and it does not take much to change their values or break connection. All relays and fuses should be checked not only for operation but for good plug contact.
Good Luck.
Hope I gave you enough, as I cannot answer further questions after I post this!!