I wouldn't rush into replacing the fuel pump just yet. I would say you have a computer problem or an electrical intermitent open, both which are wicked to find.
Assuming you would have told us if the check engine light came on you might want to inspect your coil packs for loose connections or your Crank position sensor is failing which is no surprise on those units. Attempt to locate the end of it's wire connector, clean it and re-install.