I have a 2000 Saturn SL2. When I am driving down the road and go slightly to the right it starts to vibrate just a little. I first noticed it, it seemed to be slowing down just a little bit but I am no mechanic so I have no idea what is going on. Where is the vibration coming from?
Does the steering wheel shake?
Do you feel it in the brake pedal?
I would check or have checked the suspension and steering components. I would consider these safety issues. Ball joints and tie rod ends could cause serious damage and injury. Don't let me scare you. I don't think that a slight viration requires immediate attention. However if not addressed in a reasonable period they can be very serious.
Also check that the wheel fasteners are all tight. Wheel bearings should also be tested with the steering and suspension items.