This car has a "drive-by-wire" throttle control system in which the throttle is not directly connected to the engine but is digitized and sent to a computer for analysis prior to controlling the engine speed. The speed control computer analizes the throttle input over time and "learns" the drivers throttle control habits and adjusts the engine response to throttle input based on the long-term driving history of the driver. If the driver drives aggressively all of the time then the throttle response is good. However if the driver drives conservitively most of the time then the throttle response is poor. I normally drive conservatively and I have found on many occasions that this car does not respond in a timely manner in case of emergency accelleration. That is, when I drive conservatively and then need to accellerate quickly to avoid another vehicle, this car hesitates for several seconds before deciding to speed up, even when I stomp on the accellerator. I do not feel safe in this car. I believe that this is a serious safety flaw in the design of this car. I have reported this problem to my Lexus dealer on every visit to the service department since I purchased the car new in 2000, yet they have failed to address the problem. I was told by the service department that Lexus was aware of the issue as several customers have complained about the problem. On one occasion I was told that the engineers had an experimental firmware upgrade that they were testing with some customers. I have contacted Lexus customer service, but they just referred me back to the dealership.

- Rohnert Park, CA, USA