In the last 3 mths my car has stalled going on the freeway. I loose acceleration, the lights on the dashboard come on, and I get on the emergency lane, to restart it. It will start after a jumpstart, or as I recently learned, after pumping the gas pedal a few times. It has also hesitated to re-start when after stoping (like at a gas station), when the car is hot. It will start after pumping the gas pedal. What could it be?