You're running 10 psi too high. I assume you're testing pressure with key-on-engine-off.
Fuel pressure is controlled via the fuel pressure regulator located in the fuel line manifold assembly downstream of the injectors.
There are two possibilities for the high fuel pressure. Either the fuel pressure regulator is bad or the line returning fuel to the tank after the regulator is clogged.
Are you sure it's a returnless system? Mitchell shows it as returnable.
