Any powerstroke mechanics in the house?

[jekquistk5]

With that setup, it could be either the pump or the tank. Or selector valve. But I'm guessing either tank or valve.

There are a couple of versions of that valve used by different setups. I have seen one that is switched by fuel pressure from the tank. To select tanks, you switched the different intank pumps on.

Not that way on yours, of course.
Then, I have actually seen one that was motor driven. Odd.
Most of them are solenoid nowadays I think.
But of those, there are a couple of types. One has a solenoid on each end, and one is spring loaded with a constant duty solenoid.

Its possible that it is not switching all the way over due to algae build up in the valve. There is only supposed to be two positions, but half-way might block the ports.

I gotta throw this one in, because I see all the weird stuff. Not likely in your case, but if it quits on the front tank again, try opening the filler cap.
Might have a plugged vent.

I would put money on the algae build up in the valve.

 

[k20]

Well after I did some switching back and forth it never would act up again......bastard truck.....sooooo, gonna run it some more close to home.....with a towstrap in the backseat.....and see what we get.

 

[Fordum]

Grab a hammer, walk out in front of the truck. Slam it on the bumper with the hammer. Hold up the strap in one hand, a can of gas and a box of matches in the other.

Dare it to give you any more problems.........

 

[Doc Feel Good]

I am sorry but I didnt read all the posts, do you have a fuel pressure gauge?

I just put one in my SD, and it really has been eye opening.

U should be running atleat 55+ psi at the filter housing.

I can see when I get on my truck, it drops from 65 down to about 58-60 psi.

just an idea to help troubleshoot, but it sounds like you are on the right track....