I'd still do the relearn procedure. If you do not get the idle flare-up at engine start-up, or especially if it is a little weak, the air passage around the throttle blade may be plugged with carbon. Really haven't seen that much in the last 15 years with better fuels.
The Engine Computer controls idle speed through the automatic idle speed motor on the side of the throttle body. It has four wires on it and if there's a break in any one of them, it will be detected by the computer and it will set a diagnostic fault code. Since that defect doesn't affect emissions, it may not turn on the Check Engine light. Cycle the ignition switch three times from "off" to "run" without cranking the engine, leave it in the "run" position, then read the codes as they are displayed in the odometer readout.
No code will be set for a mechanical problem such as a sticking AIS motor as long as it is good electrically. If there are no codes, you'll need a scanner to see if the AIS motor is working properly and to run a functional test on it.
Sunday, February 10th, 2013 AT 6:10 PM