2004 5-lug 2.4 Engine Whine/Whistle

There is a whine/whistle that happens almost constantly while driving. It does not happen at idle, only under 1/4 throttle and up. Doesn't sound like a belt, nor does it get worse steering or turning on/off A/C. Doesn't sound like a power steering issue either. Maybe a vacuum leak? or something in the intake? Sounds like it is coming from that area. Any thoughts before I just pull the whole thing apart

 

Just purchased a 03 Single cab with a 5 speed and 117,000 on the clock.

I noticed the same noise on mine the instant I got home. It seems to go away after a bit

Put my ear closer to the brake master cylinder and noticed it was coming from the intake area as well.

I'm hard of hearing from working around jet engines all day for years so I'm quite interested in this thread so I don't have to employ better ears to track down the whistle.