One problem related to manifold/header/muffler/tail pipe has been reported for the 2003 Dodge Ram 2500. The most recently reported issues are listed below.
The engine misfires and almost stalls. I have to pull into safe area and rev engine to restore power. This is not always convenient, like when it happened going up the mississippi river bridge on I-10 in heavy traffic with an eighteen wheeler behind me doing 70 mph. I have reported problem to dealer but they unable to help because no codes are generated by the computer. They claim that they are not familiar with this type of problem and my experience is unique. On a related/unrelated matter, the muffler has turned blue from overheating and they have told me that this is normal even though it appears like there is a restriction/obstruction in the muffler.