A new circle of hell

Last night my phone rang about 9:30, and it was John saying that he'd backed the car up over something, and the bottom hit something hard, and now it was making a funny noise and the "check engine" light came on.

I said I'd find him garage close to his house, and he could make an appointment in the morning - Google Maps is my friend. I called him this a.m. with the number, thinking he'd make an appointment. He called me an hour later, trying to tell me what the car was doing, and saying he was driving it to school, and had an appointment for Thursday, and just got mad at me when I tried to ask him more details about what it was doing. As far as I can tell, it's not overheating or leaking oil or coolant, but it's surging and the check engine light is on, and he's driving it around Milwaukee.