I have a 2005 Honda Odyssey with 201000 miles. At speeds above 60mph there is a heavy vibration from the front wheels. It is gets worse when accelerating and will smooth out immediately upon lifting off the gas pedal. I put new tires on it about 5,000 miles ago. It's my wife's daily driver so I am not sure when the problem started.
I went back to the tire center where I purchased the tires to have them re-balanced. They checked and rebalanced them but said they were just barely off and not enough to be noticeable. They inspected the suspension parts and motor mounts and found nothing wrong. I went to a very trusted mechanic and had him check it out. He was baffled after having it for three days and not finding anything significant. He checked the wheel spacers and found that they did have some build up behind them and corrected that. He found that the front tires had become slightly out of round. He moved the front tires to the back which helped some because of the fronts now being out of round, but did not correct the problem. He also checked all the motor mounts, the drive axles and all suspension parts. He consulted with a mechanic at the Honda dealership who had no further ideas of what to check.
My thought is that it could be bad struts. They are the originals and must be worn out by now. I'm thinking that while accelerating the torsion is sending vibrations down to the road through the tires and without properly operating struts those vibrations are not being dampened and causing the wheels to absorb the energy resulting in the tires bouncing. Then as soon as I lift off the throttle that torsion stops and the tire bounce stops. As soon as I reapply throttle the vibrations begin again and the longer I keep pressure on the throttle the more violent the shaking becomes, yet it stops again as soon as I lift off the throttle. I'm not a mechanic but I do have a good amount of experience working on my own cars.
So I'm wondering if what I am thinking is even a possibility or what else it could be that we have not yet checked?