Boost problem

[millertime2605]

I have an F-450 service truck and for the last 7 months I have had problems with boost during regen. I have a video to prove it and will try to attach...the video shows me going from 0-75mph with my foot on the floor. I've replaced the turbos, an exhaust manifold, the exhaust filter, and still the same. When it is not in regen, she'll run great, bout 34 psi boost, but it is just not right and want to know if anyone else has had this problem and what they did to fix it. I've also noticed that the harder I run it, the less boost I get out of it. At times, I get 15 to 22 and it fluctuates. I am a natural gas compressor mechanic and I know that if this is the way they run, Ford would have never sold this. The truck has 145K on it and it is on it's 2nd engine as of 97K so please help!!!!!!!! I've had it to Ford and aftermarket services and still no fix.