My truck didnt pass smog they said it was a firing issue and some gas isnt getting burnt..is it the spark plugs? are they out of order?

If your plugs weren't wired right you would have trouble with missing, rough idle if it would start and run. Some gas not getting burnt suggests that a tune up may be in order. New plugs, wires, cap and rotor. It would be a good idea to have the throttle body checked out, 16 years of gas flow will wear it and maybe its putting out a little too much gas. Going one hotter on your plugs could also help get rid of that unburnt gas. Make sure there are no codes that would affect gas consumption, if there is fix them first. Hope this helps.