I will provide an honest answer. I trust this will be appreciated. Please remember that a low rating PUNISHES me honest and that I receive nothing time until a positive rating is clicked.
you have asked "any idea what this could be ?"the answer is that your symptoms point to a turbo failure of some kind.
the turbos need to be checked via thurough hands on diagnostic and all related lines checked as wellPlease let me know if you have further questions. Please do not forget to click a positive rating as this is the only way I receive credit answer, thank you. Best wishes with your vehicle.