Starts and runs fine until fully warm (approx. 1/4 temp. sweep range), then dies and won't restart despite cranking fast (normal), having spark (at coil pack secondaries) and fuel sprays at rail bleeder shrader valve when depressed. It will run while using starting fluid, but again stops when that spray is discontinued. It starts and runs fine again when cold. This scenario is fully repeatable everytime it reaches full temp and restarts everytime it's cold. The "service engine" light does not come on (although the bulb works and illuminates normally during the key on test) and an Auto Zone scan doesn't show any stored fault codes. I've not yet checked the fuel pump or its relay but expect those may not be the issue, although I realize the pressure COULD be too low or the relay might be losing its signal/power supply. Other guesses are that the injectors aren't receiving a signal to open or spark is occurring at the wrong time (unlikely as it neither backfires nor cranks too fast or too slow).
Any advice, thoughts, opinions or experience with this type of problem that you may have to share would be greatly appreciated.
Thanx for your time.