I went and looked in the parking lot here at work and I'm not sure if this is it, but the wire coming from this connection runs into the bottom area of the P/S pump just behind the pulley. There is a sensor of some sort plugged in there, and this little plug I photo'd seems to be a connector coming from that and run back into the harness to the ecu probably.

Looking at this picture, there is a green/yellow stripe single wire in front of the hook on the "J" hard line behind it. This wire and connector are taped to the side of a loom of other wires. The bottom of this connector (not seen) has a black wire running to the sensor I described above.



I don't know if that connection runs from the sensor in question or not, but it's worth a try to disconnect and see what the engine idle does. If dissconected and the RPM doesn't return to normal don't quit on this being the cause. I'm not sure if just disconnecting the sensor will fix it, or if it has to be tricked some other way.