The best way to go about this is by starting with a scan tool and pulling trouble codes. If you have another key, try it. Common failures are with the wires for the PATS receiver connector, they often break right at the connector under the column.
from what i have read,a bad coolant sensor will cause this.it sends a signal to the pcm that says,hey temp is way to hot and it will not start motor,it shuts down the switch and sometimes 4 injectors on 1 bank.there used to be 2 sensors,i for the guage and 1 for the head temp that sends a signal to pcm.now in mid 1999 they changed this to only 1 sending unit.it does the job that 2 of them used to do.it is mounted on pass. side under intake manifold,hard to see and get to it.where the other sensor used to be,they put a plug in it.if you go to autozone or any other parts chain,they will list 2,1 for guage and 1 for cyl. head,this is not true,depending on what month your truck was built.i am pretty sure the ford number is 6g004.and it is called a cylinder head temp sensor,or sending unit........steve.............let me know what you find wrong