I have 94' Corrado VR6 with 90k kms... today it started making a mild knocking sound. It is there when I start moving the car till its in the 2nd gear. Once I go faster it can't be heard but when I slow down it starts again. I did look around under the hood to track the noise. I think it is coming from the belt tensioner area. And I noticed it vibrating (the tensioner). Also, sometimes there is no noise and the tensioner is stable. Don't know what it could be. Any help? I'm new owner of this well-maintained car and don't know much about mechanics.
