sounds like typical DPFE.... lil black box, has a plug made into it, 3 prongs... and 1 vacuum line that connects to it.

That code is not a firing problem, it is a EGR problem. Sometimes its the DPFE sensor. But I have seen bad ECM's cause the same problem. First check all 3 wires going to the DPFE sensor make sure they aren't melted or any damage. If they are ok, try replace the DPFE sensor.