and if your running the plate and afc housing full forward you better put a pyrometer on there


cut boots can happen pretty easy:

 

It also could be a wastegate thats stuck in the open position which is causing his issues.

Remember,he said that plugging it made zero difference and if the gate was stuck in the open position(which they can and do)it would create what he is noticing.I am not saying he may not have a boost leak,but,unless it was very bad he would still be able to get on top of the charger at some point late in the powerband.If the boost leak was that bad that he could not get on top of the charger,he would be able to hear it inside the cab.