2003 hpdi loosing fuel pressure

[Robert4599]

I have a 2003 200 hpdi. And it bogs down at 3000 rpm. I replaced the fuel water separator. vst filter, canister filter, fuel injector filters, and the two high pressure (mystery) filters. Also tested medium pressure filter and it had 50 psi. Anyway, i used the diagnostic and the hp punp reads 650 psi at idle, then at 3,000 rpm the pressure goes down to like 30 psi. I cant figure out what’s wrong. I checked the low pressure punps and they read 4.5 psi. So everything seems to be fine but it still bogs down. Anyone have experience with this problem?