When trying to start the car, it won't turn over. We were told to turn the key on, then shut off, turn the key on again, then shut off & then try to start the car. We had the car to our mechanic & he said everything checked out fine. They had the car for 3 days so they can start it up in the morning. It didn't start easily for them, so they replaced the fuel pump. 3 days later the car did the same thing. They are going to keep the car overnight to again check it out. I hope you can help us to determine the cause of the problem