for keeping your idle up when: activating the air conditioner, and when lifting off the accelerator after sustained highway cruise. I was having the same problem of RPM dropping to stall or almost stalling when turning on the air conditioner and when lifting to come up to a stop sign or exit the highway. I found my problem was, when installing the new engine bay harness, I had put way too much dialectic grease in the connection/socket coming from the IAAC to the fuse box on the drivers side of the engine bay. I traced this pathway down via the schematic in the FSM. All this AFTER I had installed a new IAAC unit and had the same problem of stalling. Once I cleaned the connector, everything worked correctly. You might be having intermittent electrical connection problems in the harness, given your additional Knock sensor code.
17:26:14 11/16/15
