problems starting car

i have a 86 gl subaru.1.8 F/I engine with 92000 mi.auto trans.sometimes the car will not start.let sit for about 10 or 15 min.and it will start.sometimes it will run days without a problem.all the dash lighting comes on,the engine turns over and everything works electric wise except the car will not start.i had this same type trouble before,except there was no electric when the you turned the key.i replaced the ignition switch and it worked fine for awhile.my altenator,starter,coil and battery are all less than 1 year old.can anyone help me or have any advise on what to check.thank you jeffreyjjm