It is amazing what a guy can learn here. I have been reading about the 7.3 and kept seeing HPOP parts listed and discussed, but no one seemed to explain the acronym. I happen to find this thread and see not only an explanation of the acronym, but an explanation of the system with awesome diagrams. Thank you for sharing Gentlemen. By the way, as a new user, I would not post to disagree with something stated by a senior user who actually knows about the trucks because of more experience. It is not a good way to make friends with guys that I will depend on soon enough to learn how to fix my truck.