Whenever I'm driving the car cuts off at least 3 times. Everytime it goes below 1 RPM, turning left or right, or when I have to hit the brakes unexpectedly( it runs fine after being the freeway for a prolonged period). Also the blinkers have stopped working & the radio cuts on & off by itself. The guy who was working on it replaced the water pump, radiator, starter & alternator. What else could be wrong?