2008 Cascadia Detroit 60 14L Loss of power White smoke

Hello, I just bought this truck in February and I am having issues with it. It has no power climbing hills (3.58 rears, 10 speed manual. When accelerating sometimes it blows a huge cloud of white smoke out of the stack which stops once I reach 1500 rpms . I am getting a fault code (ecu 128 pid 412 fault 02). Thanks in advance for all input.

 

On Monday I was under a load when I passed a Freightliner dealership that had a huge parking lot. It was easy in easy out and Im not used to that being from Florida all Freightliner dealers I pass have super small parking lots and impossible to bring in a trailer. So I decided to stop in for diagnostic and they said my trucks issues are stemming from the emissions system. I asked them what part of the emissions system and they just told me it could be anything in the emissions system... so basically they wanted to start changing parts and see what happens so I dipped out of there. Im still trying to figure it out.

 

Late post but it turned out to be the actuator as you said.