black94lude

hello guys, I have a 99 civic LX model and the past couples of week it has been giving me problem. The problem is whenever the engine get hot the engine automatic shut-off while the car is still in motion. I can't diagnose what the problem is. Also when you leave the car in the hot sun for couple of hours it hard to start the engine. It cranks and when you let go of the key it dies. Two week ago I was driving on the HWY when the engine automatic shut-off while I was going 70MPH I just had to pull to the side, it was scary. Any suggestion to where should I begin checking for. Suggestions and advices are appreciate it. Thanks