4.0 whinning noise at low rpm,Help

[88AMCOMANCHE]

Hi all .......This has been an ongoing issue for just over 2 years. Its almost like a duck ,whining noise coming from the center /drivers side of motor, but now the sound has gotten louder & worse. Its embarrassing & irriatating to say the least and I can not find out whats causing it. Its NOT the PS pump or anything along the front of the engine .......its to the drivers side about halfway back of the motor. I posted a YT clip showing all this. Not sure if it will show up or not but will post it . http://www.youtube.com/watch?v=tOsuCNeYE6g&feature=youtu.be

http://youtu.be/tOsuCNeYE6g

[Brasscatz]

Are you sure you don't have a miniature pygmy goat living in there? Man! What a sound! I have a few directions I'm thinking you should check. Is there a pulley or a fan rubbing on anything? Have you pulled vacuum lines one at a time until the noise went away? I'm pretty sure that thing in your video with the vacuum line is the vacuum canister. I've never looked under the hood of a Comanche, so I'm not positive. I also get the feeling like there's some weird vacuum leak, almost like when you stretch the neck of a balloon while letting air out.

[4.3LXJ]

Well, that is a teaser. I think that because it goes away when the engine is revved a little and that the sound modulates, that it is your idle air controller. I admit I have never seen one do this before though.

[4x4Dalton]

Thing sounds like a mini moose. I can honestly say I've never heard that noise myself either. Well not comin from a motor.

[oderdene]

I was first check all vacuum hoses and connections,

here is vacuum diagram I found,
http://i4.photobucket.com/albums/y115/512TR/FSM%20Klipp/2.jpg

http://i213.photobucket.com/albums/cc312/fiatslug87/40LVac.jpg?t=1268112116

follow the lines, disconnect, listen and reconnect :D

[Mudderoy]

Disconnect that vacuum diaphragm (I don't know what it is either) and see if the noise goes away. I think you found the culprit by following the noise. Also what is the vacuum on the engine at idle. You may have a vacuum leak and the combination of things is causing that noise.