They are probably saying that it isn't on a maintenance schedule for
periodic replacement.  It can indeed be replace - but on a 22RE 4cy is a
royal pain to do - suspect same or worse with V6.  You need to loose metal
fitting with a flare wrench otherwize it is easy to round off the shoulders
of the locking nuts.  Then undo the clamp.

 Unless you've fed the truck lots of really crappy gasoline, it
should literally be good for the life of the truck.  There is a "sock"
pre-filter in the gas tank on the pickup that stops all the bigger
chunks, and the fine dirt has lots of room to build up in the filter.

 As long as the dirt doesn't get deep enough to actually block flow,
you can leave the old filter alone for at least 250,000 miles.

  And even with the proper wrenches the filter fittings are very
difficult to get apart without damaging a flare nut.  The factory puts
them together tight enough to distort the threads.

   --<< Bruce >>--