02 with issues

[toren302]

I am working on my bosses 2002 F250. It had codes p1209 and p1211. He bought a HPOP, IPR , ICP and o-rings to fix a leaking plug on the oil rail. All have been installed and now the truck runs but very badley. At idle the duty cycle is 12-15% and the pressure is anywhere from 375-550 psi. It romps badley, and when the throttle is pressed the revs will climb but very slowly, and when the truck hits 2500 rpms it stop climbing, and then starts to run worse. I did notice the exhaust back pressure is at 20psi at idle. The valve and the tube have been cleaned. The truck passes KOER and KOEO tests. What should the fuel pressure be at at idle? I am starting to think this is fuel related. Any help would be great. Thanks.