High pitched Howl in the air cleaner tub

Move things around while the noise is occurring, and pay particular attention to the hose clamps at each end. Besides the noise, there cannot be any air sneaking in that does not go through the mass air flow sensor in that tube. If any air gets in that bypasses that sensor, it wont get measured, the Engine Computer wont know about it, and it will not command the proper amount of fuel to go with that air. Also look for any cracks in that tube caused by dry-rot. A crack or other leak that is small enough to cause an audible noise like you described is typically small enough to not have a serious effect on engine performance.

It might also just be air passing through the IAC. If this has the remote IAC, the tube leading back to the throttle body has been known to cause that also.

Thank you. You're a wonderful human being!

LOL.......................Thanks
I'm still not giving you my lunch money