Ouijan

Did several searches, but I haven't quite found the answer I'm looking for.

I'm getting a loud "sigh" sound when the engine is relatively cold and am changing gears. It is similar to other post's reference to a turkey sound, but there is no flutter (so I'm not sure if this is compressor surge). I keep the engine at relatively light loads until fully warmed up, but still hear this sound a couple times in the morning (3k / 4k, minimum boost 1-2 lbs, ligh acceleration load).

After I hear this sound a couple times and the engine is warmed, this sound disappears completely. I can only recreate this sound after the engine has gone through a complete cool-down cycle.

Any ideas on what is causing this? I'm thinking I have a sticky BoV that loosens up after a couple open/closes, but not 100% sure. Also, any ideas on how to solve the problem?

Thanks in advance.

Edit: Stock BoV AFAIK