2nd Ford with sudden acceleration !

:banghead: I have a 2004 Ford Focus and today is the second time that while making a turn, and braking, that the car suddenly accelerated for no reason. I put it in neutral, and it revvd up to 5000 rpm. I carefully reached over and pulled the floor mat and it was not causing the accelerator to stick. I let my foot off of the brake and then the engine returned to the proper idle speed. It did this before about two weeks ago. I also had a 98 Ford Explorer that did the same thing and I exchanged it for this vehicle after I hit the wall at work This is VERY unnerving . I have worked on cars for many years and have never had this problem !