870 loss of power and bad fuel mileage

[Redland1]

Would a lagging turbo,more smoke than usual,and loss of power be a turbo,or VGT air box issue or can it be something else?
I’ve had the VGT air box go bad before but that was prior to me having a boost gauge and I could tell because I couldn’t hear the turbo spooling going down the road.Now I can’t hear at idle like I used to but have boost going down the road.