funny you should mention....had a crack in the radiator and was filling every so often. Had the radiator replaced 1 month ago. Was low on fluid today. Have judiciously been watching for a basic leak, and dont see one. Was thinking that its bleading through into the engine, but id did not show up on the emisions report.
The reason I mentioned it was that I have the same misfire code pop up sometimes and it seems as though the problem is a faulty head gasket. It is supposed to be a pretty common problem on 2004 models with the v6.