In the last week my 2005 A4 2.0T Quattro has encountered - what I can only describe as an occasional steering wobble.

On a flat road the steering wheel will occasionally move, enough to make the car move and cause me concern.

This isn't caused by camber, pot holes or braking etc.

In addition when braking - occasionally it pulls to the left and other times pulls to the right.

All these issues are starting to cause me concern. Any ideas?