I'm having tempermental starting issues

[KenInKenmore]

I need help diagnosing a startring problem . I drive a 90 3.1 2dr lumina coupe .I could drive the car with no problem for weeks but every once in a while when I drive it on a warmer day I can turn it off and come back to it like ten minutes later and the starter will turn the engine but it wont fire. if I wait alittle while (30 -45 min) it will either start and run fine or it will start and not run anywhere near right... sorta like the timing gets thrown off 180 degrees off or something to that effect. when I put the obd1 reader on it, it doesn't have any stored codes. Could this be a rpoblem with the computer or could it be a sensor problem? what am I missing???

[maxwedge]

See if you have spark and injector pulse, a noid liter will check the pulse. Post back results