The engine does sound noticeably louder and "clackyer". The idle is a lot more poppy sounding like it all of the sudden has high compression or something. Clanky might be the best word for it, definitely louder and beefier sounding. I'll pull the other IP off my other truck and test it in this truck again. It was unfortunately a perfect storm in which both my 6.9s needed new IPs at the same time, one I ordered from pensecola, the other from diesel performance. Maybe both these companies sent me bad pumps? Its possible. The other truck does have trouble starting a bit. Moral of the story here is to listen to the vets of this site and pay the extra money for a pump that is rebuilt by a reputable rebuilder! My last pensecola pump lasted 5 years. However they already sent me a crap pump that I had to send back right away because the truck eo2uld fully loose power at around 2500 rpm. Maybe this replacement they sent me is 180 out. I'll swap pumps again tomorrow to see if i have better luck with the diesel performance rebuilt pump. Thanks for the insight everyone!