Ford Repair: car not wanting to start, ford taurs, crank sensor

Question
i owe a 2006 ford taurs se has 33578 miles never any problems until one day i turned the key would not start tried again it started ran fine while running.thought maybe bad gas.put premium gas in same thing sometimes it starts right up first try sometimes it takes 3 tries but so far has always started.once its on it runs good any ideas no warning lights come on,on my panel another weird thing my neighbor said one day that my alarm was going off ,on my car my car does not have a alarm i did not want to pay the exra money for it so the dearlship said they took it out what do you think stumped in vegas

Answer
first thing that comes to mind is an idle air control motor it can stick and cause a no start or start and die but usually will start running ok within few seconds-next time it won't start push accelerator half way and hold it then try to start if it does try it next couple of times it does this if it works replace iac motor

crank sensor especially in cooler climates

listen for fuel pump hum when you turn key to on position

other than those three there are still numerous possibilities you would need to have checked out before it puts you down somewhere usually at worst possible times to.

good luck.