Well, I am always asking questions and feel a bit uncomfortable. Now I want to share my experiences and things that I have learned.
About Fuel Pump & Fuel Filter:
In the first weeks when I bought my Mustang I always wannted to see when will it the fuel light turns red (by the way I was expecting red color
;everthing is so green on the cluster). I suspect why it didn't lighted although the fuel was almost emply then asked to the repairman if there is such an indicatior. I got a NO answer and a tip: From the fuel pump (which is inside the trunk) the fuel is pushed in 50psi to the engine and the unused fuel is returning back 12psi. If there is no fuel in the tank, sometimes it causes the fuel pump breakdown which means that you need to tow your Mustang to repair. He advised me have min 1/4 fuel in the tank and periodically change my fuel filter.
To understand if the fuel filter is operational or not; remove it and let the fuel flow to a container. After that if you blow in the right direction, you should feel the air is passing through.
FYI. (by the way I am not sure about the psi values that he mentioned! and how a good tecnique to understand fuel filter is operational)
I wonder if you have faced such a fuel pump breakdown problem when you have limited fuel in the tank?