Guys this just came on about a week ago.. The sound only happens on cold start.. Any idea what it is? It's not a rattle like the other muffler rattle issue, it's more of like a "shriek" then it goes away when the engine warms up.. The sound is more on the hind car that's why I recorded it there.. Thx for your input..

YouTube - G37

 

Sounds like a trip to the dealer ASAP. Could be a belt maybe... I've heard similar sounds n other cars when the belts get wet which is not what is happening with you but it could be something with them nontheless.

 

Sounds like just a really bad exhaust rattle to me. Dealership time.

 

Thx guys... Making appt with Cerritos Infiniti..