1996 LHS Knocking Noise

Hello - I have a 1996 LHS with 117000 miles on it. It works well, except that at low rpm there is a knocking sound sounding like it is coming from the right (passengers) side of the engine. When I put it into reverse and drive and don't give it any gas it does this (or slow down - if I completely stop with my brakes on it stops). However, when I give it gas it goes away. My car also shakes alot. Does anyone know what this could be?

Thank You