I've been noticing that when i turn the key to on position (not engine on) i hear this loud croaking noise when its a cold start(5-10 secs). I stepped out of my car today and tried pin pointing where the noise was coming from and it sounded like from my rear exhaust. Does anyone know what this is and is it common? How do i fix this? Please help!

 

No one knows or has the same problem?

 

Could you upload a sound clip. I want to know what kinda noise it is?