On my 2002 F250 7.3 I kept getting a check engine light when I pulled my 5th wheel uphill, I took it to a shop and they told me my HPOP needed replaced. I bought a new pump and installed it. Now my check engine light comes on and turns off during normal driving conditions. I do not have a code yet but hoping there is some idea on what might have happened.

 

Without having the codes read it's just speculation get the codes read and tell us what they are no one is going to be any real help with out knowing the codes.