1996 XLT, 5.8

My truck is having problems when I go to start it, but only if I have been driving it 30 minutes to 5 hours prior. When the truck is completely cold (first thing in the morning) or if I have cut the motor to run into a store for a few minutes, it starts very strong. When the truck has been sitting for a while after being driven, I need to hold the ignition for about 10-15 seconds. When it does finally fire up, there is a puff of black smoke and strong odor of gas at the tail pipe.

It feels almost as if the engine if flooded when I go to start it up, and it takes a few seconds to overcome this.

The fuel pressure is good, and there are no codes being thrown by the computer.

What I am wondering is if it is possible that the injectors are leaking into the combustion chamber a few minutes after the motor has been cut? I know this sounds a bit odd, but this is what it feels like. Is there perhaps a sensor that is malfunctioning? I assume that since the fuel pressure is good, that I do not need to replace the pump.

Any idea of where to go from here would be great.