We got up this morning, checked out of the hotel, and went back to the parking garage. I pulled the codes, but there were no current (non H) codes. Started the car up: bad bucking and stalled a couple of times in idle, though she would move in drive. We parked the car and I told Ivelis (my wife) that I was going to perform a visual inspection of the engine compartment.

I poked around for a minute and than - paydirt. We have a fancy, heavy, and reasonably effective Blackwing air filter. The clamp following the MAF had come almost completely detached over the previous 75 miles, allowing a stream of hot and uncontrolled air into an engine that was believing what the MAF was telling it. I grabbed my geek Swiss Army knife and realigned and retightened the clamp. Ivelis restarted the engine and suddenly Grace was back to being her usual wonderful self.