Gasoline Fuel System Related Problems of the 2005 Toyota Scion Xb

Gasoline Fuel System problem

I was driving my 2005 Scion Xb to my office. As I slowed down and turned into a parking space when I applied the brakes the engine accelerated to 3000 rpms jumped the curb and ran into the back of the building. When I reported these facts to a Toyota dealer they said they have never heard of a car doing that and it must have been a mistake on my part. Since the repair of the car in a period of two years the engine has done this four other times the repair people say they can't fix it unless it happens when they are working on the car. I believe the problem is in the electronic controls for the accelerator. I get no response from Toyota.