I recently changed hpop, ipr, oil cooler, and done egr delete. Once truck was back together it started right up and seemed to be running perfect. And then I noticed the turbo wasn't building and boost and wouldn't until it was at high rpm. At the same time I noticed I had a pretty severe oil leak somewhere on the top of the motor. I could hear a hissing sound and found the boost leak at the up pipe connection at the turbo. I thought the oil leak was coming from oil cooler seal so I changed it again and put it all back together. I still have a leak somewhere on top of the motor and still no boost. I cannot hear the boost leak anywhere.

 

Did you tighten ICP and IPR sensors? Also I was turbo cleaned? Sounds like maybe stuck turbo vanes? Did you get the seals on turbo oil line and return?