The horrible gas mileage of my 03 G35 is one of a few reasons why I'm not going with an 07 G35 at the end of my lease next month. I loved my 03 to death, but I couldn't stand averaging 13 miles to the gallon (although most of those miles were driven in the city). Even on a recent trip to Las Vegas from Los Angeles, I was only able to achieve 22 mpg, which also happens to be the best average I have ever achieved in this car (for an entire tank). If there's one thing the the G35 lags behind in respect to other cars in the same class, it's the gas mileage.

On a side note, someone posted about only being able to fill 16.5 gallons into an empty tank. From what I've heard and experienced firsthand in my 03, the reserve tank in these cars is about 4 gallons, meaning that the meter will read empty once you hit about a 1/5 tank. There were numerous times when I was afraid the car would run out of gas, but I would only be able to force in about 17-18 gallons at the pump.

Interesting because my '03 did great on gas mileage. I would average 20 - 21 mpg worse case all city would be maybe 18 and on the highway 25mpg.

Now my '07 is a different story. Lucky if I average 17-18mpg and on the highway best I've gotten was 21mpg. I wish I had my '03 gas mileage.

OK, on my return trip, (all according to trip computer). First 85 miles, average speed 61 MPH, FE 23. Then got on to faster highway. 230 miles, avg speed 69 mph, FE dropped to 20

Just drove from Tampa to Atlanta and back in my G Coupe and averaged 26.5 mpg highway. I get 19 mpg city (with lots of red lights in Tampa area).

The tank sounds a lot like my 04 Z, 20 gallon tank, DTE warning would start flashing around 16 gallons.

I am so happy, for the first time in 2k miles I am averaging over 20mpg, it looks like I will get 21 or 22 MPG on this tank of gas. 75% highway, 25% City, if it gets a bit better with good weather I will be pleased. Winter is rough on fuel economy, compound that with new car break in and I used to get 29mpg, the 19-20mpg I was getting was a bit of a shock.

Yeah, used it as much as I could. One thing I found that annoyed me about the cruise was, during the first part of the trip, it was somewhat hilly. The controller really sucks on descents. On longer, steeper hill descents, where the vehicle speed would tend to increase due to gravity, it applied the brakes. But, it would be pretty grabby with the brakes, and then it would have to open the throttle, then brake again. It was very rough and unpleasant. Almost felt like it was misfiring, it was so jerky. I think the controller needs to relax a bit and let the speed rise more on descents. And, then loosen up its control so it doesn't brake/accel so rapidly.

What was also interesting, is often when using cruise, I will have my foot on the gas pedal, applying slight pressure, sometimes keeping the speed slightly above the cruise setpoint. It seems that the controller must detect this pedal pressure, (or at least that the throttle % is greater than it is asking for), and doesn't apply the brakes in this situation.

Still, I guess I'm not that unhappy with the fuel economy for AWD, engine still a bit green. On the last 2/3 of the trip I was going close to 80. Getting 20 mpg at 80 is not too bad. I was surprised to find that it didn't drop off as fast as I would expect at faster speeds. With my Volvo, the MPG really went down above say 75. With the G, it seems relatively steady, or small linear decrease at higher speeds.

I noticed this as well. On steeper descents, it was quite jerky just like you described. It's not a big deal, but still a little annoying. My 03 G Sedan did not do this at all.

I personally can't understand the huge discrepancy in gas mileage. Babying the pedal, the best I could get is 18. In the city, while waiting for the lights I've seen it drop from 17ish to 15ish idling. Can some 07 run so rich and other run so much leaner? Those getting 26 and 29mpg, are you really sure your engine is running properly?

I am averaging around 21mpg (city/hwy mixed)

I never use cruise control in winter for safety reasons, and on a new car I never use it for at least a few thousand miles until it is broken in, I am always gradually increasing and decreasing my speeds and rpms. Because of this I can never get accurate mpg figures until it is well broken in. After that it is better to calculate your mpg each time you fill it up rather than rely on your car computer generated averages.

at 3600 miles, i continue to get the same ~19.5mpg in the city, 25 mpg on trips, not babying it.

much the same as with my 03

not great except when other performance parameters are factored in

I hate you.

Are you continuing to get poor gas mileage? Have you taken it into the dealer and have them check it out? It's strange when alot of us on here are experiencing much better fuel economy than what you are getting. You know you don't have to take it to redline between every shift right??


Completely off topic, but I noticed that Mandy Moore is from your hometown. She must be a big celebrity there eh?

you got the best cat tho