1994 Buick Lesabre won't start!

Even tho you have tested the pressure check your fuel filter, (last resort) when you turn the key turn it tothe run position and let it sit about ten seconds, then crank the engine this works with mine everytime? Notsure why it does it but. All systems checked out fine and I couldnt figure it out the only thing that I can think of is that it might be an issue with the fuel dist. System and when it sits there is air in the line from low fuel? Hope this helps atleast a little