Just got home from driving around, and it wasn't surging as bad until I briefly floored it in 1st and 2nd. I could've sworn the fans weren't running, but I felt a hot breeze on the driver side. No CEL, but ECU logged P0507 again. The video below explains what happened tonight.
https://drive.google.com/open?id=0B1...WhpbWp2cU9pNE0
Log after coming home:
https://drive.google.com/open?id=0B1...kVMX21ETmI3bUU
After shutting it down and restarting, it doesn't hang at 1k RPM anymore:
https://drive.google.com/open?id=0B1...kVMX21ETmI3bUU
I don't know... AFR doesn't look too much different, but it's in the high 14s and peaking around 15.