Important Considerations:
* Safety First: Fuel is flammable. Ensure the area is well-ventilated and avoid sparks or open flames. Wear safety glasses.
* Engine Off: The engine must be completely off and the key out of the ignition before disconnecting anything.
* Pressure Relief: Before disconnecting anything, relieve pressure in the fuel system. This is usually done by cranking the engine (with the key) several times until you hear the fuel pump stop. This is *crucial* to avoid fuel spraying everywhere.
* Correct Gauge: Use a fuel pressure gauge appropriate for the expected fuel pressure in your vehicle. Consult your owner's manual or a repair manual for the correct specifications.
If you're uncomfortable working on your vehicle's fuel system, it's best to have a qualified mechanic perform this task. Improperly handling fuel system components can be dangerous.