I too have my story of the 'Vibrating ES'. I purchased my 09 ES350 with 18,900 miles on it 5 weeks ago. On the 2nd day I noticed a vibration at 35-40 and again at 70-80. I do a lot of highway driving and found after about an hour I felt a numbing feeling in my feet and hands. I could feel the vibration in the door, the center console, the floor and, of course, the steering wheel.
The Saturday after purchasing the car, 1 week later, I took it to a tire shop and had the tires LOW roadforced and alignment checked. This did NOT fix the problem.
A week and a half later I took the car BACK to the Lexus dealership. They HIGH roadforced the tires. Still no fix.
I returned a week later to the dealership where they replaced the brand new Bridgestone tires they sold with the car with the orginal Michelins that came on the car originally. They told me the Bridgestones was known NOT to work well on the ES. They then HIGH roadforced the tires and checked the alignment again. They told me the Bridgestones were already out of balance after only a week. This id NOT fix the problem.
I returned to the dealership AGAIN 5 days later and met with their diagnostic technician who had been with Lexus since they started in the U.S. We drove the car for about a half hour. He definately felt the issue. We then drove an 09 ES off the lot with the same tires but with 50K+ miles on it. Actually this one was worse.
They kept the car for 24 hours. They 'loosened' and retorqued the motor mounts, transmission mounts and whatever else. STILL NO FIX. When the service receipt was presented to me it as all one sided and basically said "OPERATING AS DESIGNED"! WHAT? Funny thing is my 07 I traded did NOT have this problem.
I have owned 8 Toyotas and 4 Lexus and have NEVER had an experience like this. Even my big 5.7 Tundra rides better than this. I can not believe that Lexus is putting cars out like this. It looks to me as though they have joined the ranks of "ALL THE OTHER CARS"... meaning NOT setting themselves apart from the norm.
At this point I have requested a meeting with the Service Manager, the GM and/or the Owner.
I will keep you guys posted on what happens next.
Final question... has ANYONE found or experienced a FIX for this problem.