I rest my case.
You should be able to get 350-360 pretty easily if you drive sub aggressively.
I know that the light comes on really soon, but the other day I pushed it 30 miles after and It still only filled up 17.3 gallons. I filled up at 342 or something. A lot of my driving is city too.

 

About 22 around town, and 27 on highway. Not as good with winter gas - more like 20 and 25 mpg.

 

You will lose 2-3mpg during cold winter months, not because of the fuel, but because of longer warm-up times, and the colder air is more dense, so the car does not cut through the air as easily as in warmer summer months.

Example: A golf ball will fly up to 30yds further when the air temperatures are upwards of 85-90 degrees F, as opposed to 40-50*F....

 

2011 G37x

Mostly suburban driving (40-45 mph for 1-2 miles at a time).
I've NEVER gotten better than 20.5 mpg.
I currently have 11k miles.

When I hit the 20.5mpg, for the entire tank of gas, I made sure I didn't go over 3k rpms. And trust me, that was hard especially when getting on the highway.

Basically, I have two complaints about the car. First, the mileage. Second, the second row seats should fold flat. Other than that, I love the car!

 

mostly highway driving (70 mile roundtrip daily for work) and I'm getting 22-23 and I love it. great mpg for a 6.

 

I don't disagree with you that those are factors, along with lowered tire pressure from the cold, more resistance since the tires are not round to begin with and compress with every rotation (which is more difficult to compress when cold), more load on the electrical system, and others.

However, gasoline doesn't vaporize readily at very cold temperatures. So oil companies formulate fuel differently for cold-weather markets in the winter. Unfortunately, the changes that provide better cold vaporization characteristics also result in less available energy for combustion. You won't get as far on a gallon of winter gas as you will on a gallon of summer gas.

Another good reason to live in the south.

 

14.5mpg, 60% aggressivly 40% regular speeds 35/65 and traffic

 

If I really try, I am able to get 25-28 miles per gallon. But you have to keep your rpm's lower below 2,500 at all times! and try to avoid going up hills or any type of incline. Pretty much you will have to drive "granny style" lol to get those type of mpg's. The most I have ever gotten was driving 200 miles out of town and once I arrived I looked at the dash board and I averaged 31mpg's.

 

So far been at 19 mpg city with semi-aggressive driving. Went on several 60 mile highway trips, averaged 25 mpg with cruising speed at 70-75 mph. May improve since I just made it to my first 1k miles.

 

2008 G37 Commute 30 miles all Freeway about 22mpg!

 

I do 3 city 7 highway and I get around 12mpg city and 22 mpg on highway.

 

08 g37S coupe 6MT - intake, exhaust, 45k miles. Commute is about 25 miles each way, about 60/40 hway/city - computer says between 20.4 and 21.2 every fillup (and its been pretty much spot-on each time I check it by hand). Driving style is mostly restrained, with sporadic episodes of less restraint. Freeway speed mostly between 65-70.

 

17.5mpg is my average, almost all city, 5spd auto

 

Anyone check the accuracy of the onboard computer milage?

 

^^I've found for highway driving, the mileage is relatively close. I notice more disparity when the majority of driving is in the city. I've found the manually computed compared to indicated to differ by 3-5 mpg. Of course, ymmv.

I think these indicated values are a good approximation, but the calculated values is what goes in the log book.