Engine Grinding Noise problems of the 2007 Ford Freestyle

We purchased this vehicle on Wednesday August 8th, 2012. We were backing up out of a parking spot and as my husband turned the steering wheel the car accelerated backwards and the car shut off after he hit the brakes. He did not have his foot on the accelerator at all. In fact, he was in transition from the brake and his foot hadn't even hit the accelerator pedal yet. This is the only problem we have experienced since having the vehicle. I would not say it lunges forward or reverse- I would say it hops forward or reverse. It's seems to be a spurt of acceleration. The vehicle shifts fine into gear, no stalls, no grinding noises, just little spurts when it's backing up. The only difference between my husbands driving and mine is that I always engage the emergency brake when I park. I'm used to driving manual transmissions. So, when I put the vehicle into reverse I still have the emergency brake on and the spurts do not occur with my driving. I did find it alarming that with my particular vehicle it does not require my foot to be on the brake pedal in order to start the vehicle. I can start the vehicle by simply turning the key. This is not something I'm used to seeing in modern vehicles as I am used to driving Volkswagen's. I'm concerned because I don't know if this problem will get worse. Will I drive down the road and not be able to stop? I can't afford extra parts. I love everything about this vehicle (and from a Volkswagen enthusiast that says a lot). I just don't know what to do or what the worst case scenario is. I don't want to lose my life.

The first incident occurred while I was at the store with my children. We were leaving the store as I put the Freestyle in reverse, the engine made a loud "dropping" noise and would not reverse. I put the car back into park and looked around the outside to check for anything visible that would have caused the noise or lack of movement. I noticed the car idling at a high rpm. I got back in the car to try again with no luck. This is when the car surged forward. I then became scared and turned the car off. When I turned it back on everything was "normal" again. I drove it straight to the Ford dealership. They were unable to duplicate the problems and told me to continuing driving it again until I got a light on my dash to prove to them I was having problems. They serviced my transmission at that time as well to find no issues. Unfortunately, this was not covered with the warrenty so I had to pay out of pocket. Since the first incident, I have experienced this issue 5 more times, mostly while in parking lots while idle. However the last incident was 1/10/12. This surge put my vehicle in the intersection. I took the car again to the dealership. This incident had the same issues with the engine sounding like it was dropping when switching into different gears and idling high. The car would not switch out of 2nd gear while the tech test drove it with me. There was a new issue that appeared with this incident. It is a grinding noise when the gas was applied. The grind is similar to the sound the brake would make when the anti-lock were to kick in, except the brakes are not being applied. This has caused the anti-skid light and abs light to kick on. I have maintained my car religiously since I purchased it so I do not believe this is a maintance issue. Ford has been unable to solve these issues, charge customers for unnessasary repairs, and allow the vehicles to be driven.