I have never owned an American-made car. I have owned various Toyota or Lexus products for the last fifteen years.
My rigs always come with rubber floor mats. After Toyota redesigned the floor mat I had the very exciting experience of the accelerator sticking under the floor mat while boarding a ferry. Lots of luck and quick thinking prevented an accident. I pulled the floor mat right then and called the dealer and Toyota of America and told them they were murderous dumbfuck morons.
I found out later that the dealer started pulling rubber floor mats out of all of their customer's cars. This was about a year before all of the hype about sai's. The fact that my dealer took it that seriously did a lot to win back my confidence.
I do know that rubber floor mats could easily produce a sticking accelerator in some Toyota models. I never had any other experiences with sudden acceleration so have no opinion about whether or not firmware bugs could also cause such incidents.