I wouldn't have thought it would have been *too* much of an issue if that
BOV return hose was slightly kinked - It only gets used when you change gears.
Even if there is a bit of a kink, I would have thought the suction of the turbo would have been enough to get thr air through it, even if it is a bit tight.
Not too sure why it'd idle badly though? As that pipe is not even in use when idling.
Edit:
I guess when it opens, more air may be feeling the pipe, and actually causing issues with the
BOV closing/opening? Even if this was the case .. Would have thought it would cause a bit of flutter .. Not enough to cause the engine to perform badly?