2003 Lexus ES300 transmission problems

The lexus es300 has had a serious hesitation problem since delivery in march 2003. I have had it in for service several times before the accident complaining about this problem. On may 8th,2006, my wife was trying to make a left turn at an intersection and upon accelerating through the turn the car hesitated/lagged and was struck by an oncoming auto. After contacting lexus direct, they came out to test drive the auto. I was contacted several days later and was told that my lexus has no problem.

Hesitation upon acceleration. I notice the vehicle lacks the ability to pick up speed from a slow down or dead stop. I feel this in 1st-3rd gears when accelerating from a deceleration speed or stop. This is very serious and is cause for safety concerns. I just bought this vehicle and I have another problem with a clicking, whining noise when turning into a parking spot or making slow turns.