Recently I noticed a whoosh sound from my 1997 i30 upon acceleration of the engine. The sound disappears at any steady engine speed that I can bear to listen to with my ears near the engine. Opened the hood to locate the source. It sounds like it is coming from the accessory belt area. Looking closely, the idler pulley appears to move a bit laterally upon acceleration of the engine. Belt tension seems fine, and there are no belt squeals. Does that movement indicate a defective idler? (I suspect yes.) Could that be the source of the sound? Where is the bearing for this pulley? Is it part of the pulley, as in this pulley? (If this is the right part I'll replace the accessory belts while I'm at it.) This is a Nissan VQ30DE engine, manufactured in 1996. Thanks!