I have a 2002 Taurus that I purchased new and I also had a very bad
vibration. After a number tire balances and also had the dealer put new
Continental Contact Touring tires on, still had problem. I finally got
Ford to agree that there is a problem with Continental tires. After several
months the Ford representative in my area went over all the data that we had
and agreed to replace the tires again, but with different brand of tire.
Ford picked up the cost of (4) new tires and balancing and replaced
Continental with Michelin X-one. Also have them balance tires at high rpm
balancer. The Michelin made an improvement but did not
fix the problem completely. Last thing dealer did was send my car to a
specialist that balanced tires at high rpm (to simulate freeway driving) and
this balance made a huge difference. Don't back down make them fix the
problem. I was also told that this is a huge problem with Ford Taurus cars.