Seafoam
I, also, have run Seafoam in my '03. At the time, I was having an injector issue that Dodge would not help me out with. I was left on my own to fix it. Basically, I had an injector "knock" from idle to about 1400 rpm's.
After reading on the different websites, I came to the conclusion that what I had was carboning of the injector tips. To be honest, I tried a number of different products at about the same time (Seafoam, Primrose 409, Marvel Mystery Oil, etc. ) & a good, long trip pulling the trailer. After the trip, the knock went away. So, I really don't know what product, if any, helped.
The "knock' returns about once a year &, now, I just run the crap out of the truck & it clears up. I just run through the gears to redline, a couple of times, & it seems to clean up the injector tips.
From the reading I've done, & my personal experience, it seems that these new engines need to be run hard to keep the injectors clean. Guys that tow all the time don't seem to have the "knock" as much as guys like me that use the truck for occasional towing & as an everyday grocery-getter.
I've, also, heard the same thing about Seafoam that TAbbott wrote. I'd be concerned about using it on a 'regular' basis. I'm not sure if it would hurt using it every once in awhile. However, Seafoam, in general, has a very good reputation for working well in certain conditions.
Joe F. (Buffalo)