Idle Air Control Valve
Idle Air Control Valve
The IACV regulates idle speed of the engine, raising and lowering it as needed. The ECU does this by opening and closing a valve to allow more or less airflow into the intake manifold when the throttle is closed.
K-Series engined Elises use a Rover IACV (Part No. MLZ100090)
If you are suspiscious that your IACV may be stuck/jammed, you can test it by disconnecting and reconnececting the ECU temperature sender with the car ignition on (but not running). If it can move, you'll hear it chatter as it seeks to a new position when you unplug the sensor.