97 freightliner m11 celect plus miss

Got up to head to work truck start to miss in about 5th gear under load but goes away..I've noticed my mpg has went down about .5 from the usual but thought it's been from dusty conditions and filter ..I blow it out a few times throughout the month when looking things over..but the truck kinda bucks when the miss is there..anything I can check or look for before just running to the shop and wait a few days to be looked at...I've heard and read where people set the injectors as maintenance is that something I might need done ...I've had the valves service a few years back but that's it..been had this truck going on 11 years..6705xx miles on it ..it's a dump so I'm in all kinds of conditions mud dust

 

Also I want to add it's not a continuous miss it goes and comes ...more under load then normal driving

 

So could a out of adjustment injector cause this