I believe its the actually the relief valve inside the pump assembly which causes this not the check valve that I stated before. When it see's pressure exceed a certain amount (in this model its supposed to be set for 120psi I assume)it bleeds off pressure back into the tank. Neither which I believe are servicable as far as I am aware of. Yeah, sounds like a bad pump. Ideally, the best place to check this is if there was a test port on the fuel line coming directly out of the tank (I am currently making one that goes inline between the fuel pump assembly and the feed line back on top of the tank). Since we cant check it there, our only educated guess can be that its either a LARGE restriction between the pump and fuel rail....or the pump. The biggest culprit would be the fuel filter but you said its new so its highly doubtful. A pinched fuel line running back to the tank is always possible too.

I imagine you could try adding an inline pump if you wanted but a replacement pump should do the trick.

Jamie-
-AUTOMATIC turbo'd 95 Talon ESI@8psi (stock internals)14.0sec=1/4 mile

-2003 Mitsubishi Evo VIII