first question, how many hours on this motor?
this -code- refers to the crankshaft position sensor, and can be caused by a bad sensor or wire to the sensor, but experience has shown that it is more often caused by what in 'old school' would be called a 'bad tune up', or the need of a tune up. (stray spark not going to the spark plug looking for 'other/easiest path to ground' finds a path through the wire harness, sets the code).
If you have not done a full tune up on this truck, even though it feels like it is running OK, and you have over 3000 hours, do the tuneup first, and please use the correct OEM plugs, not some auto parts 'will fit' plugs, as the 'will fits' cause problems for the next person to remove without damaging the head.