I am beginning to understaand why GM offered a $4500 discount on the 2012 Impala LTZ.

This issue is purely a demonstration of poor wookmanship during the assembly process.

The vehicles have many buried modules, cable runs, and conectors and getting to them is next to impossible. The vehicle needs to be assembled with competence, not speed.

Now I have a vehicle that will not shut up (the dash rattle) at speeds above 45 mph. The last thing I am going to do is subject it to a dealearship. It will never be right after all the dashboard assemblies are torn a part and hammer back in to position. Thank a lot GM assembly, Ontario.

Dealer is really trying but I am not optimistic. The rattle is deep behind the gauges. It is more noticeable at 60 plus mph. It is also more evident in cold weather.

Update from Feb 20, 2012: Fixed. It took the dealer about a week and a hundred miles. I left the car with 26.7 mpg and picked it up at 18mpg. Some young service person had fun in my car. The dealer was Gates automotive in Martinsville IN. It turned out to be a loose inner fender liner in the right front.