general problems of the 1999 Hyundai Sonata

"check engine" light comes on and off, no issue for few months, recently while stopping at red light with foot on brake, the rpm started increasing and vehicle tried to move forward, it took me by surprise and I was about to crash into the vehicle in front of me. This happened to me few times already, and everytime it is scary. I had to push hard on the brake to prevent the car from moving. I tired to change the gear from d to n, and that helped preventing the car from moving but the rpm jumped even higher and the engine made laud noise. I took the car to a mechanic, they connect it to the computer and said the coolant temp sensor and crank position sensor need to be replaced, that is $140 parts plus 4 hours of labor. Talked to Hyundai dealer, they said never heard of this problem, and there is no recall on it, so they have to do their own troubleshoot and I'm responsible for the bill. Vehicle has about 90k miles on it, I did not fix it yet, but I'm minimizing my driving on it.

Engine check light came on. Consumer took vehicle to dealer, and they could not find the problem. A year later, engine check light came back on. This time there was a grinding noise when pressing gas. While on highway with foot on brake, vehicle started to accelerate. When changing from park to drive vehicle would rev really high like it wanted to take off. Please provide any further information.

Vehicle repair log states that vehicle decelerates too quickly.