Should the fuel system hold pressure after cycling the key with a pressure tester guage still attached?

I ran a pressure test on the fuel system. It read 62~65psi when I cycled the key. Shouldn't the system hold pressure on the tester guage after cycling the key? Because mine went instantly down to ZERO psi after cycling the key. Im trying to determine why it wont start and run unless I prime it, and then it wont idle without footfeed/or/under 1.5 with footfeed on the tackometer. Im thinking it may be the fuel pressure regulator, because the fuel pump is sending enough psi by book standards??? Please help assist me in this problem, it is a time sensative repair issue... Thank You!