It just started this weekend. When I'm driving down the road all of a sudden a very violent vibration starts going throughout the entire car...I guess not violent, but very very noticable in the steering wheel, panels, floor board, and clutch pedal. If I keep driving the car it will go away, come back, go away, etc. There is no set time it will come or go, but I can't figure out why it is doing this...any ideas??

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