Speed Control Springs problems of the 2005 Lexus LS430

Two months ago I had a sudden acceleration event in my Lexus Ls430, 2005. I was ina museum parking garage, my wife got out, I needed to reposition to not be 'on the line'. I backed up, pressed the gas very lightly and the car accelerated out of control. I slammed on the brakes and was able to halt it one-two inches from the wall. Initially, I blamed myself but then thought it might have been my floor mat and removed it. My wife remains terrified to this day. In analyzing the problem, there was a sudden massive acceleration which I did not cause and there is no way the floor mat could have caused such a problem since I barely pressed the accelerator pedal to go a few feet. I think the problem is electronic and am worried that a new spring on the pedal is insufficient. I didn't think complaining would do me any good but now that I understand the problem it is vital for you to know that my model of car Lexus 430 LS is affected as well.