Loud vacuum/suction sound?

[Tn52]

Hi everyone:
For the last few months, every once in a while when I turned off the engine, there was a real loud "whoosh" suction/vacuum sound under the hood. Did anyone experience this sound? I know that it is not normal but I cannot tell where or what broken part/s the sound came from. I cannot recreate the problem, it just comes and goes unexpectly. Help please?

2005 X5 3L, 119,xxx miles.

Thanks!

[Crowz]

Found this. Not for sure this is your problem but its something to consider.

i took apart my entire intake tract and stuck a mirror inside and spent a good 10 minutes starting and stopping my car. I finally found what causes it. As the Throttle body gets old, the motor gets a bit of play in it. When you shut the car off, there's a bit of vaccuum in the manifold that pulls the TB shut. As this vacuum pressure starts to go, it lets go of the worn TB and all of the vacuum rushes out. Hence the SWOOSH...

I have a video of how much play there is in my TB after I took it off and played with it.

[Tn52]

Thank you Crowz for the tip! Can you or anyone suggests a good source or brand for a replacement?
Thanks again,

[Crowz]

Ive never bought one of those so Im not sure where would be the best place for one.