I have a high pitch whistle when cold on idle. When accelerating it goes away. As soon as I release throttle it comes back. Once car is warmed up it goes away completely. What could it be?

 

Could be drive belts. Check belt's tension and condition (how old are they, it's 2007 car...). Could be also belt tensioner bearing (i'd say it's more likely). Or A/C pulley.
Old school way to check if it's belts (or bearings) is to remove them and hear if the problem goes away.

 

Pretty sure it's not belts, doesn't sound like a belt noise, sounds more like it is coming from other side of motor. Was thinking could be a vac leak but I can't seem to find it. Il try upload a vid to YouTube and put the url on here. Thanks

 

More information will be more helpful. But don’t remove your belts . Poor advise .

As vehicle get older and acquire miles it is not uncommon that they will start to have “quirky “ new sounds especially during the start up cold to normal drive temperatures. At this point unless you give more info or have some other problem occur, the only best way to pin point the noise is using an diagnostic audio probe or I understand not all have one in their tool box , however u can easily make a DIY version with a Philips screw driver ,small piece of vacuum or aquarium hose and a bolt or screw. If you are interested more let me know .

 

Car is running normal ect. I don't have any more info really apart from my first description. I did try diagnos with audio but just a vacuum hose in my ear. What is the technique you are mentioning? Will give it a try. Any help is much appreciated. Thank you

 

I use various sound locating tools:




DIY
Make this, push the handle at your ear and you will be able to touch the target area with the bolt/screw and sound will amplify