did you get a lot of oil coming out of the HPOP when you removed the IPR? Did you have to remove any of the fuel bowl assembly or did you just work around it?
Man I wish I knew about this site sooner . I got rid of a really nice 2000 Dually Diesel due to this same issue , dealer said they couldn't figure it out , I don't know enough about diesels so I traded it on an 08 with a V-10 . O -well .