1994 Pontiac Grand Am Random No Start

I have a 1994 Grand Am 2.3L 4cyl with 111,000 miles. The car runs great. It even starts fine most of the time. Once in a while (about 30 % of the time) I will drive to the store about 5 miles, shut off the engine and go in. 5 to 10 min later when I go to start the car, it will crank over but not start. I will have to wait about 5 hours to try to start the car and it will start up just fine, no problem. This is random and only happens about 30% of the time. I thought it was a fuel delivery problem, so I replaced the fuel pump and fuel strainers, the fuel filter and fuel pressure regulator. It still happens. No service engine light. This model year did not have Passlock either. The problem is hard to reproduce for a mechanic to do an analysis. Does anyone have an idea of what this could be? Thank You.