My 05 Chevy duramax was running fine up I-75 until I took an exit ramp to get some fuel. When I got to the bottom of the ramp and I started to go again, the engine had lost almost all power and sounded like a 4-cyl with bad preignition. It would barely make 10 mph towing my camper trailer. I changed the fuel filter right away (I carry a spare), purged the air out of it and there was no improvement in the engine power. Is this one of those things that a dealer has to reset or is it something more serious?