Blackhatch: I did a timing belt water pump on a acura integra and had the same problem where the car had a high idle and a searching idle. I called my buddy that used to work at honda and he said it almost always happens when you drain the coolant. Reason being is the two cooling hoses going to the idle air controler empty out and fill with air, causing it to go on high idle and full rich mode. All you have to do is run the car for a while till it gets hot and open the bleeder to get the air out. Just make sure you get the system filled up all the way. The code is must likely related to the way it's running, so don't replacing o2 sensors or cats just yet.