For me, it's the 4.8 (I think for the other poster Ron also). I should know more tomorrow, and at the least, if this is merely a faulty relay, it is a minor problem. My bigger concern, though, is the lack of codes for this type of problem, as the first time I brought it in (12 January) they could not replicate the problem, and only after it started overheating did they find anything.
The bad news is that these two problems (overheating/acceleration) _could_ be unrelated. The good news is that they give you a loaner car in the meantime.