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