Well at least you finally got to the bottom of it (pun intended). I forgot that little piece of rubber hose was back there (good pics !). Guess it doesn't do much good when it falls off ! Back in the days of mechanical fuel pumps on the engine I have seen a lot of good pumps get replaced when the culprit was really a rotten pickup hose near the tank sucking air. The weird thing is, they would never leak a drop of gas.