Hi all, I have had this issue since I’ve bought the car. I thought a simple hydro-clean would solve. ( I was wrong ) The car is a little lumpy at low revs in traffic and at around half way through the reves on full throttal and the same at three quarter reves under load it hits flat spots.  it almost feels like the turbo cuts out which I know is not happening obviously. I have tried capping off the EGR, I’ve taken the egr valve off and cleaned it, I have put turbo cleaner through the turbo with all the vanes open, ive checked the manifold and turbo solenoids, full service.. forced regeneration on the DPF. Checked for any lose of vacuum in all the pipes etc.. After all of this I took it to a auto electrition and the turbo is not boosting as it should? I am really at a loss with this problem so any advice will be very much appreciated. The fault code showing is P0299-(boost pressure regulation control range not reached short with power-intermediate). 

Did you ever get this sorted as I have the same issue, I have tried everything I could think of apart from a turbo.