You can rent a fuel pressure tester at Auto Zone and Oriellys , pay full price for the tester and get your money back once you return it . The tester threads on the Schrader valve located on the fuel rail , should have 31/39 lbs of pressure . It sure beats wasting money on parts that may not be needed , but if you want to upgrade the injectors to the 746 Volvo injectors while you're at it go for it .