The OEM fuel pressure relief valve is designed to relieve pressure once the fuel rail gets above 27,000 psi. Some aftermarket tuning options allow fuel rail pressure to be raised above this point, causing the pressure to be wasted and bled off through this valve. The valve can also prematurely fail, causing loss of rail pressure even on stock rail pressure calibrations. This fuel rail shim kit from H&S Motorsports will remedy any fuel pressure loss caused by the OEM fuel pressure relief valve. Common symptoms of a leaking pressure relief valve are trouble codes P0087 and/or P1011 and loss of power.