I live in South Jersey, the snow we had recently... were quite bad..(not as bad as Boston folks) but we had about 12 inches of snow (give a take a few inches)... on Sunday... traveling down from New Brunswick to the Eagles game... my car was shaking VIOLENTLY when the speed hit 70mph ~ 90mph... i thought to myself.. "oh no.. is this the DRIVING VIBRATION that most TL owners felt before...and it has finally arrived to my TL"... then... as frustrated as I was... I thought to myself...maybe it could be just the ice in the tires... the "VIOLENT VIBRATION" (feels like when tire aren't balanced) went away at 70mph, then 75mph, 85mph, then just stopped... and I was quite happy..

::knock on wood:: besides "rough start in the morning at times.. " i really don't have any problems with my 2004 TL... I got it 9/2004.. late 2004 model.

with the rough start... i've only noticed it when i get 93% octane... if i go SUNNOCO ultra 94... I always have perfect smooth start....

 

You need to clean the snow out of the wheels. Excessive snow in the wheels will make the car vibrate like the wheels are out of balance.