I also have a 2009 Cobalt with issues
i also have had this issue fir many years,ive had sway bar replaced,struts
replaced,brakes and rotors replaced tires replaced and even the
latest,controll arms replaced with the bearings and still have that horrible
banging,CLANKING NOISE WHEN I GO OVER SPEED HUMPS,BUMPS IN
THE ROAD, especially in thecold weather,the dealership and a few other
places has no idea!!! God i wish i knew what it was so i can just get it fixed
already!!!! UGHHHH