Engine problems of the 2005 Toyota Camry

My 2005 Camry has 53000 on it, very well maintained. Was driving 25 mph on a traverse when the engine suddenly died. I tried to restart the car without success. Called a towing service, however, 10 minutes later I was able to start the car and drove home. The "service engine" light remained on. At first chance I drove my car to my local mechanic who told me it was the throttle body, but suggested to bring my car to the Toyota dealer because he had seen so many of Camry throttle malfunctions that he thought there might be a recall. I took his advice, brought it to the dealer who confirmed that my throttle body was bad and needed replacing. However he told me that he could not guarantee that the "service engine" light would not go off unless I had an engine flush and a full tune-up. This did not sit well with me, so I declined the services. I paid him $100 as a diagnostic fee. When he went to get my car, the engine would not turn on at all. I called a towing company who took it back to my mechanic. He replaced the throttle and reset the service light. The car is now running, but because of my mechanic's statement and many similar throttle complaints recorded on the internet, I strongly feel that the throttle issue should be investigated.

While accelerating from a stop the car suddenly lurched forward and accelerated at a higher rate.

Sudden acceleration.

I was on my way to work when I noticed smoke coming from the hood of my car. Luckily, I was able to pull over on the service road to the major highway I was about to get on. Upon getting out of my car and opening the hood I was faced with flames. Concerned about my safety as well as the safety of passers-by, my first reaction was to try to put out this fire. I ran to my trunk, where I always keep a case of bottled water, and took approximately 8 water bottles. I was able to extinguish the fire. I am certain that, had I not been able to pull safely off the road or did not have the clear mind to try to extinguish the fire, the car would've been engulfed in flames and totaled causing serious injury to me and potentially those close to the incident. The car was towed to the nearest dealership. I am told that there is "severe damage" but do not have all of the details yet.

When I went to the dealership to buy this car they told me that the total cost for the car would be around sixteen thousand. However the real total was around thirty thousand dollars. When I notice it was too late I had already sign. At that moment I tried to fix that problem with the dealership but they completely ignore me. And just to make things worst the car doesn't function right; out of no where it just turns off. I don't know what to do the dealership does not want to cooperate. I want to cancel the purchase of this car.