Toyota RAV4 2007: Engine revs to maximum

I have experienced a similar problem with my 2007 Toyota RAV4 Cruiser L auto to that experienced by Colin Smith (Carsguide, November 9). On numerous occasions the engine has revved to maximum revs. It is quite unnerving and has scared the hell out of me. Most times it has occurred in my driveway when parking the car. I have pulled up, taken my foot off the accelerator and onto the brake and then shifted to park and the car has gone flat out to full revs with my foot nowhere near the accelerator. It's also happened twice when I have been overtaking and the car has seemed to shift into neutral when I have planted my foot to accelerate with no power for a split second, then roar to full revs which has caused me to brake, slow down and abort my attempt to overtake. My mechanic could find no fault, but thought it could be a computer problem.