I drove into a gas pumping station after driving about 30 minutes on the freeway. Turned off the engine to wait my turn to pump. Cars ahead finished, and I tried to start - nothing but cranking after a brief spurt of engine rev. No lights indicating a problem, and still about 1/2 tank gas in car. Cars behind had to go around me - laughing. Finally after much cranking the engine came to life with a brief period of increased idle speed, and has been normal on starts etc since this episode. Any clues?