I installed my fuel pressure gauge into the side of the fuel pressure regulator where there was a shrader valve to test pressure. so the gauge wasn't reading anything so I bought a fuel pressure tester and hooked it up. I read 0 psi with key on and 10 psi with truck running. I guess you can shim the spring but if it is my lift pump how do you test that? I thought I read it should have 50 psi. any thoughts or tests that I can run myself?