The idle speed on the 4 cylinder is supposed to be 700 rpm + - 50 rpm. To test if it is correct cut a small strip of wire and connect the TEN and GND pins of the diagnostic plug under the hood to each other with the engine warm. your idle should be within these specs. If it is not then adjust it through the screw on the throttle body untill it is within spec. After you disconnect the jumper wire from the diagnostic plug the ECU takes over and will put the idle within spec no matter what but this keeps the adjustments from being more than they need to be.