djponthego

We experienced the same problem with a 2004 HR Abassador with a Cummins 330 hp. There were no alarms displayed nor problems. It kept getting worse and finally lacked power to climb hills in 6th gear regardless of cruse on or off. It acted like a fuel problem. I changed the primary fuel filter and it was better for a bit. Finally I changed the secondary filter and everything was back. Lots of power, held in 6th up hills and better than I had remembered. Maybe a possibility for you. The problem went away with the filter change. Maybe the pressure into the injectors was low enough that the ecm made the shift due to low pressure. All I know is, the problem went away with the change of the secondary fuel filter. It only had about 12,000 miles on it. Give it a try. Darel