i just got 11 mpg....... at first it was about 13-14 and i thought it would be normal, but now its 11 mpg... i only have 50k miles.. what could be wrong...

 

Sometimes I think someone is siphoning my gas.

 

Anyone have any ideas?? I range from 11-14 mpg.. I don't think this is normal lol

 

that doesnt sound normal, but you're better off asking G owners in SoCal rather than Canada, our climate is very different from yours so some of our factors would affect you

 

Could it be snowtires & winter thats making a difference?
This is my first year on snow tires and im seeing a drop in mileage...ive wanted to fill up to the top and see how much mileage comes out of a tank, but right now gas prices are too high to fill a tank of premium and measure it lol

 

snow tires if anything would make you more efficient in the winter

 

Look here and you can see what mileage other Infiniti drivers are getting.
http://www.fuelly.com/car/infiniti

this one is mine: http://www.fuelly.com/driver/pmccartney/g35

Your spark plugs should not be a problem at 39000km. If they are then you may have bigger problems. Hopefully not.

edit: I just realized this isn't a new post

 

Should I bring it into a dealership to get it checked or where? I know for sure I am getting <15 MPG.. It averages about 13/14 ...

 

^ If you have warranty then go to the dealer otherwise find a trusted mechanic that knows these cars. Ask the So Cal guys for the best shops.