Metallic Clatter @ 2300 RPM?

Odd noise issue with my '06 LGT. There's a metallic clatter from under the hood at about 2300 rpm. It happens on acceleration and deceleration, definitely in 1st, 2nd, and 3rd gear....not sure about 4th and 5th because engine/road noise may be obscuring it. It happens whether the car is in gear or not, and whether or not it is moving. If I keep it at 2300 rpm, the clatter will continue until I change the revs. If I'm accelerating or decelerating quickly, there will be just a quick chirp as it passes through 2300 rpm. This has been going on for awhile, doesn't seem to be getting any worse, and I can't detect any other problems. Car has 145k miles and is in excellent shape. No mods except Borla catback.

Any thoughts? I'm stumped.

have you changed the oil recently? if so did you see any metallic in it? are you sure its not an exhaust shield or something of that sort?

hate to say this but to me it sounds like a rod knock. my first motor would do the same thing if i would rev it up to 3-4k rpms it wasn't audible at any other rpms but every rod knock is different. my motor was screwed wasn't even worth fixing, needed everything. id advise for you to check your oil to see if any metallic is visible in it.

but make sure its not something simple like a shield or something like that. get a buddy to hold the revs while you listen where the noise is coming from.

I would think its a heat shield.

Good luck.