This just began yesterday......it only becomes audible starting at 5000 rpms. It sounds like a scratchy chatter sound coming from the engine. The car was fully warmed up. I dont often take the engine speed up that high but it concerns me none the less. Has anyone had a similar issue? Could this be valve chatter and what excatly does that sound like? Thanks in advance.

 

Dito. Most noticable when I depress the clutch.

 

This noise seems to be isolated from the clutch. It sound the same with the clutch in or out, as well as the car in gear and in neutral.