I noticed over the past few days I have been getting heavy vibration during acceleration, when I hit 45-65 mph all is smooth. I can step on the gas and it seems to be ok.
My first thought was a u-joint, they seem all tight. I can hear the engine and it seems to be running smooth during this problem.
Tire out of balance - bent rim? Check the inside of the rim to see if any dirt, mud, snow or ice is packed in there to make the tire/wheel out of balance.