I just wanted to add a reply to let you know your problem isn't being ignored. As blazer94 said...most of us aren't too famailiar with 5.7 TBIs.
I don't have any experience with the 5.7 tbi so after reading your post the other day I started searching. I could not find any related TSBs. I searched a lot of other forums and visited some websites, I found a lot of people experiencing the same symptoms as you, it seems to be a very common problem. From what I could tell, no one has found a solution yet. Some of them have replaced lots of parts with no success.
I don't want to make any "guesses" until after I do some more searching.