Alright. I just got all the plumbing run for my nitrous set-up (wet shot which includes a fuel pressure gauge). Anyways when I prim the car (turn the key one click forward till the fuel pump turns on but car doesn't turn over) then turn the key back to the off position... I watched the fuel pressure gauge slowly go down. Maybe 1psi per 1-2 minutes. I checked all the lines and nothing seems to be leaking. I guess im just paranoid that I have a vapor leak or something. I've driven the car around and nothing seems to be leaking but I want to know if it is "normal" for the fuel pressure to slowly drop at the rate i'm seeing. It is a mechanical gauge by the way. Any thoughts would be helpful.

 

If you're losing pressure in the fuel system when the pump shuts off, there are a number of possibilities:

-check valve in the fuel pump is bad - hardest to detect

-fuel pressure regulator is leaking - check the vacuum line for fuel

-injector(s) is/are leaking - pull the fuel rails up, pressure the system, and look for leaks

-leaking lines or fittings

If it stays above maybe 30psi after the pressure starts to drop, you will probably be OK. If it drops to zero while you're watching it, you have one of the above problems.