I really appreciate you making this guide, this problem has plagued the states cars for years it seems, there is a guide over here, but it's not quite as good as yours
I think it's possibly the sulphur content in the fuel, it's really crap over here compared to the UK, either way, it's a sucky fault, manifests itself in various ways, but it's all the same thing.
Ironically, mine is an '04 as well, really needs this doing, once it gets to a quarter tank, it drops like a stone, but then will recover and do the same thing over the course of the next few days driving until i really don't know how much is left in the tank