I've got a 2008 cobalt and I'm kind of stumped. I was getting vibrations around 50 mph, and they got really bad if I hit the brakes. So thinking it was warped rotors is replaced them and had the tires balanced. That helped but still wasn't gone. So I replaced the front hubs, didn't improve anything. I've done the left and right/push pull check on the tie rods and there is zero movement. Any ideas on what to do next?