Auto Parts: fuel pressure gauge specs, fuel pressure gauge, 1987 pontiac 6000

Question
I have a 1987 pontiac 6000. We have tested the fuel pressure(it reads 9), but we do not know where the pressure should read at. We have called 2 auto parts stores and they say 2 different things. We think we have a fuel pump issue, but without knowing what the gauge should be reading we don't want to replace something that might not need to be replaced. Please help. Thanks

Answer
    That pressure is way too low for a fuel injected engine.  If my memory serves me correctly you should be seeing about 45psi at the injector.  While it could be a leak or a plugged filter (please don't replace the pump without also replacing the filter) it is most likely the pump.  The car is certainly old enough to need a new pump.