Intermittent problem starting a 1995 Ford Mustang

Intermittent problem starting a 1995 Ford Mustang (5.0 L with Automatic and 96+ K miles). It will crank but won’t start. After a week of trying, the Ford dealer could not duplicate the problem. They checked the battery and the fuel system and found no problems. The car has recently passed a CA smog test at a test only station. The problem does not appear to be affected by either hot or cold environment or length of time that it has been sitting. However, if it needs to be cranked three or four times in order to get started, invariably it will not start at all the next time a start is attempted. I have tried to use OBD 1 unit when the engine check light comes on and the engine would not start. However, once the unit is plugged in, the car will start, and therefore unable to capture any error codes. I have replaced the Idle Air Control Valve and still have the problem.