Originally Posted by gary c

You will receive error codes if there's anything not working correctly. One thing that helps mileage is using your cruise control whenever possible. You didn't post the number of miles on your G, if it's close to 100K you could be ready for plugs and all the other maintenance suggested at that mileage. Claims of 19 mpg probably include city/highway mileage and a close calculation of mileage from a full tank to the next.
Gary

Originally Posted by ScraggleRock

Check it out:

All these weird things people talk about that are out of the ordinary are not things people do normally to get good mpg. Getting goof mpg has to do with maintenance and driving style.

Make sure you're up to date with differential, transmission and engine oil changes, keep your spark plugs changed every 40-50k (I don't care what anyone else says), keep your tires properly inflated, your air filter clean and don't drive 80 everywhere you go. Also, no red light romps on the gas, or excessive passing.

O2 sensors DO progressively degrade, but you wouldn't see a significant decline in mileage unless they were actually broken, so changing them now wouldn't result in much.

Originally Posted by Quisj95

Ohh yea sorry about that I have 104000. And I do plan on changing the plugs and belt soon. I'm now thinking about the air filter too. Would you recommend anything else?

Originally Posted by Quisj95

Wow thanks I actually warm my car up for about 15 minutes almost everyday. And no my temps are good and I have nankang ns2 Tires on the front and idk what tires are on the back but they look like performance tires

Originally Posted by millenium

Would you look at your Vin # of your 07 G35 Coupe and see if you have 7M9 starting around the 11th digit ? I know its off your topic but I need to verify this referencing the
Rev up engine for 07 coupes only.

Thanks !