one way check valve

i’ve been dealing with a slow start condition for a while and i did confirm with a pressure tester that my check valve was letting fuel back into the tank. but i’ve been noticing it’s gotten a little bit better. i don’t have to prime my system a few times anymore to get it going but it’s still...

I have 2001 4.0. Long crank issue. I check my fuel pressure at the fuel rail. Cranks up to 47 psi. As soon as I turn the engine off, it drops to almost 0. From what I have researched, pretty sure it is the one way check valve in the fuel pump assembly. Some say the check valve in on top of the...