Focus ZTW 2.3l engine idle tapping/ticking sound
 

I getting a tapping/ticking heard from the inside the car (not the engine bay) at idle when the outside temp is 20 degrees F or below and at start up with engine cold. A trip to the local Ford dealer found no problem. The car runs fine. Is this sound normal? this is my first winter with this car (2004 Focus ZTW)