Re: 2005 Ford Taurus-Starting Problems
When you first turn the key, all the warning lights come on. Look for the Check Engine/Service Engine Soon light. Then crank the engine. IF the computer is getting good signal from the crankshaft sensor, the light will turn off. If it stays on, you've found your problem. Replace the crankshaft sensor.
If it does go off, then I'd suspect a bad coolant temp sensor. Takes less time and money to replace it than to test it.