having trouble with fuel pressure on my 03 mach 1. at idle, its only 15-18 lbs. I have changed everything in the fuel system. new fuel pump, it's an aeromotive 325 lph pump, I have a Kenne Bell boost-a-pump set to 25%, new fuel filter, new FPDM, new FIPS, AND STILL only 15-18 lbs at idle. My vacuum is 21 1/2 inches at the FIPS, and I'm getting 5.1 volts to it. if I disconnect the harness to the FIPS, vacuum increased to 22 inches and fuel pressure goes to 40. any ideas ?