Boost pressure

[JimT]

You should also check for exhaust restrictions. That de-mandated DPF could be clogged up if it wasn't done correctly, causing excessive back pressure that the engine/turbo is trying to overcome. I would also take a real good look at that turbo. If it isn't the cause of the problem then it's probably suffered greatly as a result.

And, as others have said, you need to have the ecm program looked at by Rawse or someone else recommended here.