Hello. So I just bought a 2007 trailblazer LS. I replaced the control arm on driver side. I have a vibration I cannot seem to get rid of. I don't know how to decide if it's a motor mount or something else entirely. I was putting it in neutral at lights and that would cause it to stop until I put it in drive again. But it doesn't happen constantly. If it is a mount wouldn't it do it every time driven? Any help would be greatly appreciated. Thanks!