Rhythmic vibration can be felt through gas pedal at speeds above 65mph (frequency approx 1-2 secs), tires balanced and no improvement. Vibration not experienced at lower speeds or when accelerating at lower speeds

Hello, tires, wheel balance, wheels out of round, tires out of round, or axle shaft balancing issues are basically the only possible causes. Have the tires and wheels checked very well. Then have the vehicle lifted to check the axle shafts - one or both could be causing the vibration and could need to be replaced as a result. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops