Okay, car had no codes (1444) before I started working on it. While replacing hoses, I disconnected the AFM, the fuel injector electrical connector down on that black plastic box under the manifold, and the electrical connector on the ICV. I of course reconnected all of those on reassembly.
Now it idles fine, usually runs fine with good power, but it sometimes stumbles right off idle, and it'll die on return to closed throttle every single time. And it's showing code 1215, air meter. What should I do next?