my truck only gets 13 to 14.9 miles per gallon.can i do anything to improve.

No actually thats pretty good ....

Probably not much. Less warm up time, less idling time, take your foot off the gas as soon as you see a red light or stop sign ahead of you (coasting saves gas).

I work at my Buddies used Carlot & we get alot of those trucks, plus I've owned one & ur getting about the best if ur getting almost 15mpg.! Don't know what tires u got but that makes a difference.