06 3500 srw with 120k on it. On vacation with the family. Towed the camper (~10k fully packed) out to VA beach. Truck did fantastic on trip out. This week have had a couple instances where the truck was hard to start....it would crank and almost start and then I'd have to turn key again and it'd fire fire up. Exhaust sounded funny (like a slight knock) to me once but after popping the hood it sounded normal under the hood running and exhaust has sounded normal since. I dumped some Lucas in the tank yesterday and truck has ran fine since. I'm worried about an injector and I'm a long way from home....need to tow 6 hours or so back to PA Saturday where I leave the camper during the summer then another 4 back to Ohio. Not sure what I should do. Any advice?