4.0 not holding fuel pressure

Hey guys. 2006 X-Runner 1grfe 245k miles. Having an issue where I have some sort of internal fuel system leak. No extrernal leaks present.
System holds 45 psi when running. And does run and drive perfectly fine with no codes. As soon as you turn the key off though, fuel pressure drops like a stone (goes to 0 within seconds). This is creating an extended crank before start condition but only when the truck is warm for some reason. Cold starts and hot starts are fine.
I have already replaced the oem fuel pump with a walbro 255 and urd external fuel filter kit. Replaced the fuel pump again because I thought maybe I got one with a bad check valve. Replaced the FPR on the fuel rail with an OEM one, and replaced the injectors with low mileage(19k miles) oem ones out of my buddies truck and no change.
Only thing that I had spotted on the fuel system that I dont even know would effect it is on the fuel return hard line. Where it connects to the soft line with the quick connect back near the gas tank. The fuel line has a plastic coating on it. When I had the lines off, I noticed a crack in the plastic on the very end of the hard line. I cut the loose piece off with a razo blade. Its only the very tip of the hard line now that has the plastic coating removed. No external leaks Like I said but maybe the seal is compromised? My only issue is I can not find the hard line part number/replacement. I checked on Toyota parts and could only find the flexible line that connect to it.
Any ideas on if you think that could be my issue or something else?

 

So I finally got the issue fixed. When you install an aftermarket fuel pump in the factory sending unit, you use a piece of submersible fuel line to go to the fuel pump to the nipple at the top of the sending unit. Many people will tell you, you should not use a worm gear clamp to hold this hose on as it can cut into the rubber line over time and cause it to fail. Instead you are suppose to use a spring style clamp, so that is what I did.
But apparently the spring style clamps can not hold enough pressure to keep it from leaking and that was my problem. Switched out the clamps to a smooth internal worm gear style clamp that I could tighten decently and now the issue is resolved.
Sometimes you have to do the right thing the wrong way