All of the sudden my car started to shake more then normal. In neutral and reverse there is no shaking or vibration inside the car. It only does this when I am in drive and stopped, when I speed up the vibration seems to go away. In parked there is only a slight shaking/vibration. I don't think this has anything to do with it, but my car now makes a low muffler noise when I try to speed up all of the sudden. Any advise will be great.