actually its an 18 gallon tank. and i get around 340 to a tank on average. sometimes a lil lower sometimes a lil higher. i average 19mpg which is half city/half hwy driving and i try to drive decent 60% of the time. lol im gonna find out what my complete hwy mpg will be when i drive up to jersey sometime soon. only mods are hks knock-off dual exhaust, cai, lowered on wheels set to 38psi.

 

Not likely. I don't think many, if any of us have gotten 29 MPG ever.

 

Stay away from the cheap gas. I know mine started to get a little sluggish.

 

Well I dunno what to say. As far as I've read, and done, I cant get above 16. I couldn't get that mileage out of a GTI, even though I always drove the crap out of it. I dont see how anyone even gets above 18.

 

Sounds like you need a tune up I'd start with the basics fresh oil/filter new air filter (AEM dryflo will be money well spent) and lastly plugs at 85k they're getting close to the end of their lifespan OEM recomends 105k IIRC but IMO thats too long, I usually change mine around 75k. I don't have a G but I rock a VQ ( Maxima )so I know a little about these engines, and I think you got the point of only using super so I won't beat a dead horse, but I will add make sure you use top tier fuel here is a link with info on that. It will definatly help keep the VQ running strong and clean.
http://www.toptiergas.com/

 

We got 20gal tanks.. at least coupes do.

My gas light comes on when I reach about 300 miles.

After the light comes on, i'd say there's about 3-4 gallons left. So i'm roughly getting 18mpg.

Sticker numbers are 18/25 but i don't believe the highway number for a second. It probably assumes you're driving 55mph the entire time.

 

I averaged my mileage from 3 separate tanks. Topped it completely off, and ran it pretty much below E. Got 22 mpg with a mix of city and hwy driving on all 3 tanks

 

My light comes on right at 360-370 miles. I consistently average 22-24mpg. I only drive it hard every so often. Also have a 2K SE MAx with an old VQ30 and average no less than 20 MPG on midgrdae gas. Your car has 85K, you get what you pay for. At that high mileage on a car, who knows how it was maintained or driven. Changing all of the filters and fluids is not a bad start but, you just might be toast. I drive my car hard after any mod install and I never average less than 20 MPG, at all. GL with the car, it's a beauty. Great color.
BTW, all my numbers are on premium. Only the absolute best for my ride.

 

I work for a top tier gas station, and its the only gas i put in my 07 MT. Im getting about 400 per tank and i was complaining about that.
But to be helpful, and repetitive, better gas, tune up, air pressure, shift at about 2200 to 2400 rpm's, don't have your windows down, causes a lot of drag.
Oh yeah, almost forgot, coasting will get you better gas mileage. Although it is illegal i think and you may have to pay for it later in brakes, but you wanted to save on mpg.

 

I will definitely follow every tip I'm getting from you guys... Another thing to add, here in FL is freakin freezing for the first time ever, so I'm not even using AC...so, I would say that I'll be getting 14mpg, holy crap!!! Now thing is certain, I love the G despite all this ****, its my secondary car anyway... Now, starting my project next week bro, I WILL GET 320mpg +++ on this ****, that's my goal. On my next fill up, I'll put Premium and for now I'll add an Octane Booster to the 87 currently in. Lets see what happens.

 

Wow bro, 320 mpg? Thats pretty impressive. Let us know how that turns out.

 

The coupe is 16/21 MPG for city/hwy

I don't know what conditions you're driving under, but I get the average 18 MPG driving in the suburbs.

Those people who are getting 20+ MPG are driving the highway, so I wouldn't try and relate to them if you do any stop-and-go driving.

 

uhh skip that octane booster.... just wait and refil with that good $hit

 

80% of my driving is city and Im averaging 22mpg

 

The only way you're going to get 29 MPG in a G35 Coupe for a full tank of gas on the highway is if you were to set the cruise in 6th gear and drive nonstop on a flat, smooth, straight long highway for about 7 hours straight at about 50-55 MPH without any crazy spurts of acceleration and bursts of high speed driving. It would be very unrealistic, boring, and slow, and not worth the monetary savings to get the extra few Miles per gallon that you would get in comparison to making the same trip at about 70-75 MPH and getting 22-24 MPG on the same drive.


You should:
-Definitely use premium fuel
-Change the motor oil(it may be old), and use a quality synthetic oil
-Check your tire pressure and make sure it's at around 33-35 PSI in all 4 wheels.
-Run a bottle of Chevron Technron fuel system cleaner through your car the next time you fill up
-Consider Seafoaming the car through the brake booster
-Make sure you don't have a sticky brake caliper on any of the wheels and your parking brake isn't dragging
-Shift at lower RPM's in normal driving situations and don't romp on the gas real hard(The first gen VQ35DE Coupe motor gets its best fuel economy cruising on a flat road at around 1700-1800 RPM's)
-Make sure you have a clean air filter... switch to an Amsoil EA Nanofiber filter
-Don't drive with the AC on unless you really need it. Using the front window defogger will automatically turn on the A/C, and if you drive with the HVAC system on AUTO, it will bounce back and forth between AC On and Off repeatedly.... so you may want to just use Manual mode and only put on the front window defogger when the windows get foggy.
-Drive on the highway with your windows rolled up... windows down adds a ton of aerodynamic drag to the car and will be a serious detriment to your vehicles economy.
-If you have a ton of miles on your car, you might want to change your spark plugs(70K+).
-Is your check engine light on? It might not hurt to have a buddy who has an OBD-II scanner check the car for stored trouble codes or CEL codes. I've seen situations in the past where shady dealers would actually break the light bulb in the dash cluster for the CEL light with a pair of pliers so that the CEL light would not turn on, and they could sell the car to unknowing customers as if it were healthy.