My Cobalt Is Doing A Weird Zinging Noise Its Gets Worse As I Pick Up Speed There Is No Affect On My Performance I Think Its A Exhaust Leak Under The Drivers Side Of The Car Or Its Something On The Back End Of The Motor Any Ideas?

 

When my 2.4 was doing this, the dealership ended up replacing the cat and it i went away. If it's under warranty, may be worth getting that checked out.

Outside of that, may be a heat shield vibrating?