Crown Vic fuel pump issue.

I would check fuel pressure. And another thing to look at is the idle air control valve as well

Its possible that either the in-line fuel filter or the in-tank fuel screen is clogged (or both, such as from a huge load of rust/crud in the fuel tank) to the point that there is not enough pump pressure to force sufficient fuel through both of these filters for all starting/driving conditions.. IF that's what's happening, th eincreased back pressure on the fuel pump may very well be what's making the noise more noticible. One tipoff that its a clogged filter is that generally when the engine dies it wwill easily restart after a minute or 2 as during the down time the already presurized fuel has time to work its way through even a mostly clogged filter. Another tip its a clogged filter is if teh engine runds fine undera light load (idling or driving slowly) but dies or bogs down when rapid accelleration is required. Another possibility is that the fuel pressure REGULATOR has failed in such a way that it is now requiring increased pressure from the pump to force fuel that THAT.