At idle you can hear a ringing from under the hood. Give it a little gas and it gets louder. I have the Rumbler cat back so I can't hear it while cruising. Any ideas? Idler pulley and belts were changed 2 years ago.

 

Sometimes a rock or bolt stuck in between the header tubes at the collector will do that.

 

its your AIR pump

 

tensioner pulley bearing?????

a/c compressor????

power steering pump????

 

The AIR pump should go off after the car warms up. Plus that's a humm more than a ring. I've heard of people with some problems with the AIR tube check valve when using headers, but I don't know what it sounds like...

 

Remove the belt and start the engine. See if that eliminates it, and work from there.

 

Definetly not the air pump, this is a ringing noise instead of the hum. Thanks!