I get a relatively high pitched whine from my engine. It goes up and down with RPM.

I've confirmed it isn't anything powertrain related (it makes the noise in P or Neutral when rev'd).

I suspect a belt or pulley bearing. All belts are in good condition and properly tensioned.

I've had someone step on the gas while I listen, but can't figure out where its coming from other than in the front area of the engine.

Ideas?

 

Take off the accessory belts one by one, until the noise stops. If you remove all 3 belts and its still making noise, then its under the timing cover ie Water Pump, Idler, Tensioner bearing, etc etc.

 

There is a tool that may help with this, it's like a stethoscope but it has an aluminum rod on the end. You should be able to get one at most parts stores.
http://www.amazon.com/Lisle-52500-Me.../dp/B0002SQYSM

 

My 2001 4-Runner is doing the same. Likely under the timing belt cover. I had the belt changed at 180,000 miles and am at 188,000 now... I'll let you know what the tech finds....

 

Mine had a similar problem. Removed the belts one at a time as described above. My noise was on the AC belt. The idler pully is known to go on these rigs if you wheel them. You could loosed that off and see if the squeal goes away?