I have a fuel system problem. on 1990 Buick Riviera

The car is hard to start, and when started runs real rough for a few minutes. From everything I have read, its either the fuel pump, the fuel filter or maybe the fuel pump relay.
Using AC Delco parts, what would this cost to repair/replace.

Asked by for the 1990 Buick Riviera
we love our 1990 riv and the money was well spent getting the new pump. we did discover that the pump did not solve all of the problems we needed to omit the pulseator between the pump and the line . what it was causing was slow pressure build and fast drop off when pump stopped .it was leaking and dumping the fuel back into the tank.
you can witness all of this when you hook up a pressure gauge at the test port and apply power to the pump test wire on the left side of engine bay next to strut tower it will be green in color on the end .
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probly more for repairs than what the car is worth check fuel pressure first you can buy a salvage yard one pretty cheep