Hi, Mark. Sorry to hear about your ordeal. I live in Boston and also had fun driving today, though my car performed flawlessly. One question I have is might you have sucked in some water into your intake during one of the splashes you drove through? I have witnessed (not today, a few years ago) a BMW driver drive full force into what was obviously a deep pool of water (higher than the hood of an average car). His beemer stalled right in the middle of the mini-lake and I watched his headlights dim as he tried to re-start it (the water was covering most of his headlights). I have never seen anything quite like this before. I am not saying you did anything remotely as silly, but those puddles out there today were pretty impressive (I saw many drains spout water like fountains in Belmont). So, your car may have ingested some water through the air intake. If I were you, I would try Prospero's suggestion and if that didn't help I'd take it in to the dealer. You will need to read and reset the codes that caused your check engine light anyway.

Good luck.