Alright, so I grabbed a fuel pressure gauge to do some more in depth tests with the fuel system since the fuel pressure regulator came up for the hard start issue.

Here are my results on a bone cold car:

-When I turn the key while the pump is priming the gauge goes to 56psi.
-Immediately after the two seconds when the fuel prime prime shuts off the gauge drops to 49psi.
-After 10 minutes the gauge has dropped to 43psi.

Plan is to let this sit overnight and see what it says in an hour and then in the morning. Then I will continue with the engine running test with the cold start and pull the line from the FPR as well. In a few days I will also do a hot engine prime, start, and FPR test. The car is partially apart right now in the garage for some other stuff so I can't drive it right now.

I'm using this PDF for my reference which says the prime should be between 52-59psi: https://www.google.com/url?sa=t&rct=...EyzTfaexkx7Tsw

However, I am a little confused as to which reading I should compare that to. Should I compare that value to the prime pressure of 56 or the pressure immediately after of 49? The reason why I ask is because I am following this troubleshooting guide for GM fuel systems http://www.fastfieros.com/tech/fuel_pressure_L67.htm. I know it's not for my specific engine, but it's for a 2000 Grand Prix with the 3800, so even though the exact values may not hold true, the diagnostic procedures should be pretty much the same because the fuel system setup is similar. In this specific guide in step 2 it says to observe the pressure with the fuel pump running and compare it to the specification (which matches the guide I gave above for that engine). Then in step 3 it says the pressure may vary slightly when the pump stops running, but to note the pressure after it settles out. Then start the 10 minute countdown and watch for a 5 psi drop from that value.

Anyways it looks like I pass the initial prime test, but slightly fail the leak down test. I don't have the shut off valves, so where the fuel is leaking I cannot determine. I'm definitely not going to crimp the brittle plastic lines to find out! Maybe this is something to follow for my hard start issue or rough idle issue after all? I'm questioning leaky injector because my long term fuel trims are pulling fuel at like -15 at idle if I sit long enough, but fine everywhere else.