Koyo ALL 2JZ Timing Belt Idler Pulley 13505-46041

This pulley should be replaced when doing a timing belt service.  The bearings inside become worn out, and if neglected can fall apart and potentially damage your engine.  It's a relatively inexpensive part for the peace of mind.

This component is manufactured by Koyo in Japan and is identical to the ones Toyota sells at a much lower cost.