Low Fuel Pressure

[MDOC111]

The Burb has started to idle rough and stall at times. I checked the fuel pressure and the highest it got was around 58 and the lowest was around 50 and that's running and just with key on. It never got over 60 psi. I have replaced , fuel pump, done the spider conversion, intake gasket, and complete tune up all within the last two years. Is there a way to determine if it's the pump or the valve thing next to the spider?

 

[MDOC111]

If leave the gauge hooked up for a couple of minutes, it doesn't drop below 45. I'm leaning towards replacing the fuel pump now since it doesn't drop down to zero.