With the vacuum line to the FPR disconnected, the fuel pressure in my 93 245 measures 55 psi. at idle. With the vacuum line to the FPR connected, it drops to 45 psi. If I connect a hand vacuum pump to the FPR, the most it will drop to is 41 psi. After 40 minutes with the engine off, the residual pressure is 24 psi. The Bentley manual says the pressure at idle (with the vacuum line disconnected) should be 43.5 psi. I'm thinking either there is a restriction in the fuel return line to the tank, or the FPR is bad. I understand that the main pump has a check valve that regulates the flow back to the tank. Could this be bad? How do you check this? Thanks.