If you have such a valve, it was installed as an aftermarket modification. Check with whoever installed it.
YES you do.
its in the fuel tank
On top of the fuel tank.
There is none.
Bad sending unit in the fuel tank.
My first guess would be the fuel pump is at fault.
this is incorrect. The fuel pump is located in the fuel tank. It is a lot of work to replace. I have done it twice on my 97 blazer. Its expensive too around 300 bucks. The fuel pump on a 1997 Chevey blazer is right beside the engine
19 Gallons.
fuel pump relay?
It is attached to the bank of fuel injectors (the spider) under the upper intake manifold.
60 to 66 psi
I know that the 1 on the far left is the fuel relay