Well, it's been two weeks and I figured I post the dealerships results, given that there are 88 views to my original issue, at the time of this post. It took the crew at the dealership 3 days to come to a diagnosis. (Not that I find that unreasonable. It simply takes time to work through an issue's cause and effects to come to the appropriate conclusions.) The culprit? A bad ECM (engine control module). With an oil change, the ECM part and labor the total came to $1,350. Most might be upset by the amount, but I figured I've been well off in terms of car repair costs so far. That, and after two and a half weeks without a car, I was definitely ready to get mine back!