B8 s4 hiss/whistle/pressure release noise when car shuts off

[NOThatDangeRuss]

Not sure why this is happening. Perhaps a vacuum leak? Feels like a lot of pressure is coming from the hose above the intake that use to be held in place with the oem on e and now rattles to its heart content. Also minor leak of either oil or power steering fluid. (Leaking near front passenger forward control arm. Any help would be swell. Took a video.

https://youtube.com/shorts/ENzYUkFTFtM?si=0Vu_6b2W6QmdDnxI

Thanks!

Also any Audi mechanics in the ct area wanna help install mid pipes crank pulley for a dbl pulley set up and rs grill?

Thanks I appreciate y’all.

[Nillious]

I know that some time after the car is off mine will release the pressure in the hpfp. Sounds like a sudden pressure release similar to opening a soda can.