I just found out this problem in my 03 G35 sedan.
The outside temperature is around 25 c and when I start the car and a/c some wire smell come out from vent. After running for 2-3 minutes the smell just gone.

Does anyone know why and what I should do? Send the car to dealer to do a a/c cleaning service will help?

Thanks

 

it's the mold in your air filter... from now, try turning the ac off a few minutes before you turn the car off, so the moisture dries in the vents/filter.

as for now, you can try the mold-remover things that you spray into the vents, or just get your air filter replaced

 

^+1

It's common in a lot of cars.

 

Yup, it's normal, occurs when first starting vehicle and a/c shoots a quick blast of stale air in your face... boo

I've found that running the a/c off or on heater just before shutting down seems to help, as is switching to fresh air rather than recirculated a/c, I've also seen some people use ozone treatment in the a/c system which seems to work, ( though the ozone odor isn't exactly roses either )