Starts then turns off?

"Started and running continuously by hitting the fuel tank" is a clue the fuel pump is going out here is how you can change it out to fix the problem in the images below. Also 50 PSI is low, another clue the fuel pump is weak. Fortunately, the fuel pump was a tap door under the rear seat, so replacement is easy. Also check inside the tank to make sure there is no contamination or water rolling around in the bottom of the tank. Check out the images (below). Please let us know if you need anything else to get the problem fixed.