94 Buick Century with 54,000 miles. It feels like the tires need balancing. New struts, new CV joints, new top of the line tires balanced, new front end alignment, new harmonic balancer, brakes checked out, torque converter solenoid replaced and converter checked out by three of the topt shops in town. No vibration until I hit 66 MPH then it starts like a harmonic vibration, increasing with speed. Unruly at 70 mph. vibration has a steady rhythm like three shudders a space, three more shudders, a space and so on.