Stock wiring for basically everything is marginally sized, small amounts of corrosion, dirt even just loose pins in the wiring plugs can all conspire to each lower voltage a little. I would begin with inspecting every connection in the fuel pump circuit and the cable to the underhood fuse/relay block. Check the fuel pump ground too.

The fact Fred and I called this as an electrical issue right away while dealerships just kept swapping pumps should tell you at lot about how little "technicians" understand as compared to enthusiasts. "technicians" are rarely capable of diagnosing much unless the computer gives them a code.

 

Thanks for the info. I start checking the why the volts are low.