My 20007 pontiac grand prix make a wineing noise when I start the car then be come less noticble when warm and the check engine light come on and went off three weeks prior to this elevating problem
First check your power steering fluid. The power steering reservoir is behind and under the alternator. It is kind of a pain and you will more then likely need a flashlight to see anything back there. If your power steering fluid is normal then it may be a battery going bad or an alternator going bad. If your battery is starting to go bad in this cold weather it will take a lot to charge it after starting the car and the Alternator needs to work overtime to charge the battery. This could cause the bearings in the alternator to whine or squeal. i would start with these areas first.
in addition to this answer , check your transmission fluid as well. This can make similar noises when cold. would indicate low fluid level or tranny is getting bad.This would be your last option. $$$
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