Had intermitten metalic rattle sometimes on cold startup. Tensioners had already been replaced. It finally was heard at the repair shop and turned out to be the idler pulley. In case someone may have similar symptons!

 

mick, I went through the same thing on my 98 once. These idler pulleys can make a heck of a lot of noise when they are bad.

FYI to folks reviewing this in the future. I was able to diagnose mine as bad once I relieved the belt pressure and spun the pulley by hand. It clearly displayed a feeling of "steps" as it turned.

What do I mean by steps? Let me say it this way: If my ear was closer, I bet I'd hear it make a click click click noise 20 or 30 times per rotation. A properly operating pulley is smooth as silk.

John