Hi guys! About 6 months ago I bought my 2006 G35 Sedan, and I absolutely love it! I bought it with 19 inch coupe wheels, lowered on Eibach Pro Kit Springs, a CAI (WITH the all important heat shield so that it isnt a HAI ), and it has some form of a sport exhaust on it. It has everything I would've done to the car already on it, and I paid a very reasonable price for the car.

Now for the problems... the main one being my atrocious MPG. I AVERAGE... get ready for this... 13 MPG, SOMETIMES 14 or 15... with mixed city and highway driving. I do not drive like a lunatic. There are new tires on the car with the correct PSI. It has been professionally aligned. Recent fully synthetic oil change. It runs great! It doesn't smell like fuel, so I dont *think* that its running rich.

Any ideas before I take it to my mechanic to see what the deal is??

 

Sounds about right. The G35/37 don't get the best fuel economy.

 

how many miles on it? have you changed the spark plugs? any trans issues? check engine lights?

 

The deal is mostly your driving style and/or the mods that were done to the vehicle

Having owned both a 06 G35 6 speed manual and my present 2012 G37S my MPG on road trips is very similar.

A round trip from NJ to Florida this past April



Short trips in Florida are clearly reflected.

Telcoman

 

You should probably confirm what other modifications have been done to the car...and check on those spark plugs or maybe your O2 sensors. How many miles are on the car?

I have a 2005 G35x (AWD) with 100k on the original motor/transmission and I regularly get 14+ MPG via nearly only city driving. I just got 22+ MPG on the highway with the AC on and some traffic. With that in mind - you should be getting better mileage than that if you're not smashing the skinny pedal.

 

When I tried dipping down into the lower grade fuels I got numbers consistent with what you show here op. Try a new gas station.

 

This too. I only use premium.

 

I get about 20-23 combined hwy/city and that's when I baby it. When I'm taking it to pound town I get about 16 mpg. Are you related to Mario Andretti?

 

Good luck with that, unless your filter is completely enclosed except for a feed of air through the grill like the stock set-up you've got an HAI. Sorry to burst your bubble.

 

In town only, I get about 16-17 mph, mixed 20-21, road trips so far just under 26 mpg averaging mostly 75-80 mph.

 

When I slapped on the 350 pumpkin, I lost a significant amount of MPG

 

6 speed cars are geared pretty low, noticed it with my 6 speed Maxima too. 2500 rpm is 70 mph in my car. In my Accord, I'd be going well over 80 at 2500 rpm. So no surprise my G35 gets worse mileage than my Accord at freeway speeds.