Ok so I've finally made a video about my mysterious engine bay noise. It sounds like it could be 3 things that come to mind:

-bov diaphragm
-belts
-seals or rotor hitting housings


its sounds like it could be really minor but at the same time really serious. If you were wondering I am running premix.

 

belts

 

Tough to say but the fact its when you transition from on/off throttle I'd like agree with the above statement about belts.

 

belt squeal.

 

thanks guys, ill be looking into it. Is this due to too much tension or the opposite? I also may have spilt some power steering fluid somewhere.

 

if the belts get loose they start to Glaze and lose grip.
From what I can see is that you are revving up the belts are fine, and then when the car is decellerating the pulleys are slowing down before the belt does..so Squeal.
The best solution is new belts and proper tension.

 

much obliged misterstyx69. Your explanation is exactly what I wanted to hear, thank you~