Crank/runs for few seconds/sputter/die/not start/wait period of time/starts/runs great/never dies.

Engine always cranks, but sometimes doesn't start. This happens after the car sits over night or on restarts after driving. Wait a few hours and it starts again. The car never misses and runs great at any speed without any misses. Here are the error codes from AutoZone when they ran the check engine light diagnostic.

Note: I had the cadillac converter checked and it is in good condition.
1 A/F ratio concern
2 Air leak near HO2s (Heated Oxygen sensor) bank 1
3 ignition system concern
4 Faulty Cadillac converter

 

If you can get the specific codes (like P1234) for your car that will help.

1-2 should not stall out the car.

3 may be your stalling problem

4 the catalytic converter shouldn't cause the car to stall out unless it was completely clogged and you would have running problems all of the time.

If you live near an O'Reilly's, they should be able to test your ICM to see if it fails. Other parts stores may be able to do this.