Water, trash, or air in my fuel ?

[Werther]

I have had many issues with my 89 F250 stalling while driving at various speeds, both highway speed and nearly idle. First i replaced the fuel filter, no change. There also seems to be no difference between front or rear tank either.

After it has stalled, while I am cranking, the water in fuel light is on, but very faintly, can barely see it glowing in daylight. While the truck is in the process of stalling the water light is not on. I have drained the water separator numerous times, and have collected as much of the effluent as i could the last few times, but I cannot see any water in it when emptied into glass.
I have also tried a few bottles of iso Heet to help move the water through the system.
Then i put a new fuel pump. Drove it up the road feeling like it was fixed, but it did the same thing again after switching to the rear tank on the way back home. I'm guessing trash in the tank, or water.

When it does stall I try to restart by just cranking first. Sometimes I drain a bit off the water separator and crack the no1 injector line and crank until it catches or the batteries die.

Any Advice?