Update: So I have escalated this to the Southern CSM and he is an asshole. I told him that I had been doing research and people who have had a similar problem as I did and were able to get the car to a dealership while the light was still on have been diagnosed with a throttle body failure. Since I have the 125K-mile warranty (and am well within that), can't they just replace the throttle body? If it works, then I'm out of their hair. If it doesn't, the next time it happens, I drive it to a Toyota dealer and trade it in . Not only did he say no, but he ridiculed me on the phone, AND when I expressed concern about my safety (I commute over a very busy bridge with no shoulders; if I stall out there, I am probably dead), he said, "You can't live your life afraid of dying."
I have further complained. I'm not sure there's anything they can do at all at this point to make me happy. Most likely when we pick up the car on Monday, we will drive straight to trade it in. I am so angry that I am having to get a new car in less than three years.