My Audi A4 has a strange rhythmic clicking noise while the car is idling or driving. I can't seem to find the source of the noise. The noise can be heard in this following video
Found the issue, it seems to be the EGR Valve. The rod or lever is lose inside which rattles up and down while air flows through.
does the clicking follow the speed of the engine as it increases? If it does, does it click at crankshaft speed or cam speed(1/2 of crank speed). a metal rod touched to the block does wonders as a stethoscope to pinpoint where a sound is actually coming from