I began noticing my car making a zooming noise when I accelerated it would get louder and louder but then slowly quiet down as I slowed down. I could hear the humming/rattle noise as soon as I stated my engine it would hum and intensify. When I drove it it would drive normally without any motor power issues and normal when turning but I was nervous because it grew louder, not good! My 2007 Chrysler Sebring currently has 159,960 miles on it and I keep decent maintenance on it...I've replace a few things that years later became recalls...convenient! Anyway, I was researching and came across this post and finally I felt like this is it! It's something wrong with the alternator system, so I told my BF who just laughed and was like that doesn't make sense bcz it's chargin properly. I started off small by checking the idler pulleys both upper, lower and tensioner. They all seemed ok except one., they're bad when you spin the wheel after taking them off and it makes a chirping/tiny squeal sound So I decided to replace the lower/upper idler and tensioner pulleys along with the serpentine belt just to see if it would fix the noise and NOPE! Still make rough idle sounding noises So praying I decided to go back and get the powersteering pump because I might as well it's never been replaced and a new alternator. Only had time to put in the alternator which is super heavy and could not install it without gently unbolting the AC compressor. (disconnected the ground from the battery so that it wouldn't arc the alternator once the wires etc where clipped and bolted in place. Put the S belt back on and NO more scary noises!!! I'll be replacing the powersteering pump soon since I bought the part in case once I research how to do it! New alternator was an easy fix! Runs better than when I started hearing a noise!

 

I have a 2007 that had the same type of issue and found it to be the alternator. Take the alt out and go to a auto parts store and have tested for free.