This could be a few different things. You need to check the following:
(a) Check to see if you are getting spark at plugs
(b) Check to see if you are getting fuel at the TB
(c) Check air intake
(d) Dumb but have to ask, any fuel in tank :-)
Also need to know: anything happen prior to you turning off the truck? Any recent repairs done? Check the above and let us know. Can not give an honest or accurate answer without the above.