is your truck new or is it well used? if you didnt give it after run oil last time it was used and its been a while, fuel will often gunk up the motor or fuel lines if left to sit. some fuels are worse about this than others. turn it upside down with the plug removed to see if its flooded, if fuel is spitting out of the exhaust stinger and is not starting. also you may try checking the head bolts for tight fit, compression is muy important.