The fuel pressure rinning should be between 44 and 54 PSI. When you shut it, the pressure shouldn't drop below 30 PSI for 5 minutes. If it does drop, you have a leak. Try this:
Start the engine and allow it to warm up. Next, clamp off rubber hose portion of fuel line pressure test addapter between fuel rail and test port T on fuel line pressure tester adapter. NOTE SHUT ENGINE WHEN YOU CLAMP THE RUBBER HOSE. If the pressure does not fall below 30 PSI within 5 minutes, the fuel rail or an injector is leaking. Next, do the same, but place the clamp between the rubber hose of the fuel line pressure tester adapter and the fuel line and test port T on fuel line pressure tester adapter. If it doesn't fall, the injectors and fuel rail is good. That leaves a fuel pump check valve, fuel pressure regulator check valve or a leak in the fuel line.
NOTE: A slow pressure leak usually indicates a bad check valve in the fuel pump. A quick drop usually indicates a bad check valve in the fuel filter or regulator.
Let me know if this helps and what you find.
Thursday, March 19th, 2009 AT 9:46 PM