Fuel Pressure issue?

I have a 2000 Saleen SC 281 4.6. Little while back the car would stumble on hard acceleration. Fall on its face really. It's not modded except for a smaller SC pulley. Ran fine with it in the past though.
New coils and plugs, changed FPR, checked MAF and TPS but did not change, EGR working, new fuel filter. Fuel pressure gauge at the rail is reading about 30PSI at initial start up and quickly goes down to approximately 10PSI at idle. Checked pressure with FPR vacuum line plugged and unplugged. Same result. Even if I account for a few PSI lost with the gauge it seems really low. Idling in neutral and flick the throttle it falls flat and bogs until I let the throttle go. I'm thinking new fuel pump but I'm not as versed in these engines as I need to be.
Any suggestions would be appreciated.
 
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