My 1993 Saturn SL1 starts up fine when the engine is cold (like in the morning) but stalls during the day after the car has been running and theengine is hot. And then the car will not start. It turns over but the engine does not seem to be getting gas. The "check engine" light is on. The fuel pressure regulator has been changed but the car still stalls. Any ideas of what could be causing the problem????