After years of starting and driving, I parked the car and a few days later, it won't start. Egine cranks good but just won't start. Check the fuel switch located in the trunk, it is ok. Pulled a spark plug and found no fire to the plug. What do you think is the most probably cause.(like some sensor, maybe the crank position sensor)? If so, where are these sensors located? 1997 Lincoln Continental.