As Im coming to a stop or going in reverse once in awhile my car will just shut off. the lights and radio will stay on but my engine dies, and the battery light will pop up. so i put it in park turn the key in off position and then turn it on. and it starts right up with no problems. It also when i go to press on the brake my RPM's will go really low almost to 0 and the car will shake like it wants to turn off. what makes my RPM's go so low and why is my car shutting off randomly.