I have a Westpro fuel pressure guage installed at the at the schrader valve on the injection pump and I see around 12 PSI at idle. I have a Hypertech programmer and on stage 3 at WOT I can pull the pressure down to 1 to 2 PSI. The lift pump is new so I don't think that is the problem. My question is, is it better to measure the fuel pressure at the injection pump or before the filter?