Timtom

After driving about 30 miles I shut the car off, visit friends for about 2 hours. When I try to start the car it turns over but does not start. The next day it starts as if nothing happened. This has happened three times at the same location at three month intervals. Car has 150,000 miles, fuel pump and fuel filter has been changed (no help). I'm thinking ecu has to be changed but not sure. Any thoughts?