One problem related to accelerator stuck has been reported for the 2003 Lexus RX. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Lexus RX based on all problems reported for the 2003 RX.
As I was driving the car started to speed up uncontrollably and would not slow down even with the brakes applied. I had to put it into neutral to apply the brakes but we went from 45 - 85mph in a matter of seconds while driving in 45mph zone in the inner city. When I turned the car back on while in park the accelerator was still stuck up to 100mph + so it was not drivable. We found out later from the mechanic that the throttle was sticky and stuck in the open position.