i have a 2009 g37 coupe my check engine light came on not too long ago. I took it in about 3 weeks ago to get the light checked out at autozone and it showed code P0447, EVAP system. a week later and make car has now started to make this strange hissing sound. It is more present around 2800-2000 RPMS while decelerating. Also when I start my car and it is a cold start, you can some what hear the hissing like a constant sound, but one the rpms go down it goes away.

Has anyone here ever had this issue? also could it be my fuel pump or the valve that Autozone suggested? First thing I did was replace the gas cap, and that did not do anything.

 

I think that evap hiss is a vacuum leak. Get it checked out pronto.

 

Ok will do, would you recommend taking it to Infiniti or to a local indy shop?


also what are the consequences of not getting it fixed in time?

 

The shop needs to able to check the entire evap system. That usually involves putting light pressure on the system while injecting smoke. They look for smoke in all the wrong places.