With the fuel rail pressurized, engine off and key off, should pressure be relieved when applying vacuum to the pressure regulator valve?

When I apply vacuum, the pressure drops slightly then rises again when I stop applying vacuum. Just curious if this is normal.

Mark

 

I found the answer in my Bronco II Shop Manual.

Applying vacuum to the pressure regulator valve should release pressure by returning fuel back to the tank. This is the method Ford states should be used prior to working on the fuel system.

Mark