Help define this noise/rattle (could it be worn Drive Belt)

[epapp]

It sounds like a pulley is wobbling around...it seems like more than just a squeak as it has some harsh rattling as well. Pull off the belt cover behind the seats and have a listen

[haz]

Thanks, will do. And how do I determine if it is a pulley? I am not an expert opn these engines.. (THe sound is only a few seconds after a cold startup and dissapears after I touch the gas pedal..)

Edit: is this what you mean, epapp? http://www.pelicanparts.com/techarticles/Boxster_Tech/17-ENGINE-Idler_Pullies/17-ENGINE-Idler_Pullies.htm

[haz]

Any others?

I found parts numbers for all of these:

99610215166 POLY-RIB BELT
99610211958 DEFLECTION ROLLER
99610211757 TENSIONING ROLLER
99610211856 DEFLECTION ROLLER

Should I just change it all or is it worth removing the protection cover and inspect which rollers need replacing? The belt wil be replaced for sure.