Chevrolet Repair: 1996 chevrolet 7.4L vortec 1500 conversion van, fuel pressure regulator, flood mode

Question
Normal start and operation, after reaching engine operating temperature restart requires full throttle to restart, idle is then high. Engine stalls if selected to dive or reverse after idle returns to normal 15-20 minutes later operation is normal with intermittent missing when driving or stoping and driving acceleration.

Answer
It sound like you may have fuel injector(s) or a fuel pressure regulator leaking fuel into the combustion chamber or intake manifold causing a hot soak flood condition. By holding the gas pedal to the floor you put the system in clear flood mode reducing the amount of fuel that is sprayed by the injectors.

I also would not rule out a vacuum leak ie: intake manifold etc.