Getting a high pitched whining sound that increases and decreases with accelleration and decelleration

Could be one of the belts slipping or worn out. Might even be the water pump bearing. Does the whine increase/decrease as you rev? Whine louder if you suddenly accelerate?

remove the belt and start the engine ..IF THE NOISE disappear it might be idler bearings that driven by belt but if the noise still there check the pcv valve..

Could be your alternator or a bad idler pulley. Is the transmission good? It may be the tranny or your differential whining.

check the belt tensioner.

I had the same thing and it turned out to be a bad Idler pully which eventually went bad and tore up the belt. note one bolt on the idler has to be reached from underneath the car.

sounds like you need to replace the idler pully and maybe the tens. pully. and that will solve your sounds problem. whats happening is the bearings are bad and thats what you hear

This could be anything from the pump in the transmission to the alternator bearings/bushings to the power steering pump. Could be an idler pulley bearing, but I doubt it.
Hint: If the noise is very high-pitched, check the alternator. If it is a lower, medium-high-pitch sound that changes some when you turn the wheels, check the power steering pump. If it is almost like a moan or a "Whooo" sound, that's the transmission pump.

you could be low on transmission fluid check that and make sure it registering properly on the dipstick.

You may have a bad idler pulley. Locate it, spray a lubricant (WD-40) behind it. You don't want to get it on the belt surface. If the noise goes away, you have found the problem.

Could be several things. WHICH ENGINE?.. 4 cylinder (has three belts, power steering/water pump, alternator & A/C compressor, one tensioner pully A/C compressor), The V6 2.7 (has only one belt, 1 Idler pully and 1 tensioner pully), the V6 3.5 has two belts - A/C/alternator, and power steering - there are two tensioner pullys). Noises can be caused by the belt(s) themselves, pullys, bearings, pully bearings, water pump shaft bearings (or belts/pullys rubbing up against something). Let's not forget that there is also belt(s) behind the Timing Belt cover as well as pullys and bearings associated with the timing system. You could start by removing one accy drive belt at a time (alternator, water pump, compressor, power steering, etc) to see whether or not the noise goes away in each case. If after each case, you discover the noise is still there, it's probably behind the timing belt cover (idler/tensioner pully, water pump shaft bearing, crankshaft bearing, etc.). Good Luck