Having boost issues in lower gears where the turbo struggles to kick in but once it does it works fine and works fine in higher gears. Had turbo actuator replaced, egr replaced, dpf checked.

Started a little self diagnosis today. Here is a little video of what it is doing

youtu.be/-we_2hbi6kM

Needs sound but, to clarify, start of video the turbo actuator is unplugged. I plug it in and you hear a hissing whistle, engine strains then a few seconds later it seems to just let go. Withe sort of air pressure escaping noise.

I believe the part in question is the