I just got my cobalt SS 05', its got 44 k on it. when decelerating I"m hearing this scary knocking/loud squeaking noise, when i hit the brakes or the accelerator even a little the noise will stop, its super loud in 2nd gear and almost as loud in 3rd. you can hear it in all gears but its loudest in these ones. almost feels like something is majorly out of balance, but the tech's at gm inspected my car last week and said the cv's look good and didn't see anything out of the ordinary under the car. i did just get new tires, but it was doing it before i got the tires and i watched them balance it with my own eye's so its not tires. any help in telling them where to look would be greatly appreciated!?