The only thing of that could make a clacking noise while the key is in the 2nd position would be the ValveTronic motor try to calibrate itself. There are 2 motors under the engine cover, one on each side. If the noise is coming from either one, you have valve train problems. This could cause the motor to backfire! You probably need to get the car to a proper mechanic, before any more damage is done.
Last edited by HerbP; 01-23-2013 at 05:39 PM.