bought a 2007 Pilot with 20k miles on it 3 weeks ago from Honda dealer in Brandon, MS. It's been back for service 3 times since for shaking and vibrations with driving at low and high speeds. Pilot was a Certified Used vehicle with new tires. Dealer has balanced and rotated, test driven each time. After the 3rd time in, they said that they do feel the problem, can;t find any bulletins on it and don't know what to do. They even test drove other used pilots on the lot and experienced the same thing. Wanted me to drive them to see it was happenning What's going on here???