I have a 1999 Ford Expedition which stop whiled driving this morning. I checked under the hood and saw where coolant resovoir was empty. I replaced but car still would not start. There were no signs of overheating (no lights on dash, no smoke etc.) Replaced the thermostat and top hose, recharged the battey and it still will not start, it sounds like it is trying to start but like it is not getting any gas. What else should I check or can be causing the problem?