Truck issue

hey guys figure your the best to give me some advice was headed to Nashville and my truck started to shack under a load if I backed out of it it was baby smooth like always. I had stopped to let the girl take some pics and it started to rev up only thing I was thinking is please don't be running away I ran back to the truck but then it just went back to normal idle so I'm at a truck stop on 40 I'm all out of ideas on what it could be I'm driving a Ken worth with a Cummins in it

 

That's what I was thinking talked to Ken worth service guy he said prob not filter but made since to me it might be had to go drop my trailer pulling up hills it shook pretty bad then bob tailed back to hotel now it seems like it's almost normal very light shake,,,, when it started doing it today I was still bob tail hadn't got trailer yet

 

Hey guys I'm at the shop in Jackson Tennessee now I'll give ya updates when I figure something out

 

It's a 97 Cummins motor