High pitch whine on idle

My VX started making a high-pitch noise/whine when I don't press the gas. Basically when I start it cold there is no noise... then few minutes later as it warms up it starts making a high-pitch constant noise coming from somewhere in or around the engine. As soon as I give it some gas it goes away but comes back when I let go or idle... any ideas wht could be a problem? It is pretty loud so I think it could be something serious... I can't quite pin-point where exactly it is coming from. Any suggestions are appreciated.

Thanks

Since you mentioned no idle or other engine issues, I would say it is a bearing on the alternator, power steering pump, or ac compressor. It could also be the fan clutch. Have someone look under the hood and listen while you give it a little gas and the area of the whine should be relatively easy to isolate.

Thanks Tone for the suggestions. I actually tried to identify the source of the noise myself - I opened the hood and tried to find where the noise is coming from while on idle and could not pin-point it. It seems that it is coming from the right side of the engine (if you are looking from the front) but not certain... when I press on the gas cable in the hood to give it some juice the noise goes away but returns as soon as I let go.

AC or power steering then.

Check the hose that connects to the pcv valve. A vacuum leak will make a noise like that. Shawn

If you can't tell what accesory it is comming from, get a dowel or broom handle 2-3 ft long. With the enging running, and without getting the dowel wrapped in the belt or smacked by the fan, place one end of the dowel on the accesory or it's mount. Then cup your ear to the other end of your dowel. The accesory that the noise is comming from will be noticeably louder.

Mustangs idea works with pvc pipe also, any diameter. Just BE CAREFULL not to get close to a belt or fan. Helps to plug the other ear also, btw

You can try replacing the oil filter..sounds funny, but i have had 1 do the same thing, also had one on my amigo do the same thing,each time it was the oil filter, i couldnt believe it either!!