Noise from engine 617.952

[Gordo]

I did a search for engine noises and could not find anything like this. I don't have the technology available to let you listen, so I will do my best to describe it.

Background:
I notice it only above 2000rpm and only when the engine is warm. It is most noticable under deceleration, probably because there is less other stuff to cover it up. It is slowly getting louder as I drive the car more. This is a daily driver. I commute about 30 miles in the mountains at hwy. speeds. The first hints of the sound started about a month ago.

Description:
Scratching, metallic sound that is intermittent. It comes in short intervals about .5 sec every 1-2 sec. It sounds a little like snow studs on a dry road. I hear it best from inside the car, although I can reproduce it with the hood open by revving the engine.

I have also noticed a slight loss in power. Perhaps just my immagination.

Thnks for all the good advice.