accessories, ac, pwr str, alt, serpentine belt idler pulley, smog pump. A really long screw driver and the human ear is an amazing old school diagnostic tool. Could be a bearing beginning to squeal. As always "actual results may vary".

Nothing specific, but if engine speed has no effect, that leaves the running gear, or air around the body. If it changes in close relation to the vehicle speed, then I would suspect running gear, hubs, drive shaft, or tranny and transfer case. Last resort, make sure the vent windows are closed all the way.

JLF

Check your vacuum lines for leaks or cracks

IIRC, the idle air control motor will start whistling under some condition and I have totally forgotten why. It's been forever since I've seen this. Seen it happen on the crown Vic's with the 4.6 also. If you haven't resolved it by Monday shoot me an email at sixgun 452 at yahoo dot com and remind me and I'll dig around and see what I can come up with. Also, just for grins, check your PCV hoses and fresh air intake duct work for vacuum leaks. It's very common for Ford vacuum hoses to deteriorate and suck holes in them and also very common for folks to leave the PCV vent side hose that plugs into the fresh air intake hose off.

turn the radio up you won't hear it any more.

I'm thinking power steering pump fluid is low or the pump itself is feeling it's age

Bob