When the wheel and the tire rub together.
A defective vacuum line can cause a whistling sound when the vehicle is accelerating. A loose belt can also create a high pitched whistle sound.
Fuel is not good!
check your swaybar links and bushings
mine is a 2001 QX4 with the same problem. as far as i know, it could be a bearing problem.
bad wheel bearings
Sounds like a brake wear indicator. If it changes while braking then it is. Recommend a brake inspection.
Most likely it's a CV joint.
if its a front wheel drive vehicle then it could be the axels
Low coolant causing air bubbles in the heater core.....
you probly have a belt slipping, a can of belt dressing should stop the sound
main shaft bearing
More than likely... the power steering belt.