This weekend I plan on putting a fuel pressure gauge on the injection rail ,after flushing it as you suggested and see if I can get a better idea of what is going on. The fact that I can turn on the ignition key for about 10 sec before cranking, and it starts right up, makes me think that it is some how loosing pressure and or fuel in the supply line.
One thing I did not mention is that when the engine starts, there is a strong smell of gas fumes outside the vech. and this is a problem when the engine is hot or cold.

Thank You