I just bought a used 2005 Ford Focus zx4 that has 100700 miles on it. When i start it up its really loud and the whole car has a general vibration to it. I've researched it and thought it to be the motor mount but I saw a video of a guy who had a motor mount problem and his vibration was violent. Mine isn't completely obnoxious like that its just a constant low vibration. I'm having a mechanic look at it tomorrow but I figured i'd check here to get some opinions on what to look for.