HA!!!! i got all of you beat. i average 15 city/highway.

 

That's actually not a ridiculous claim if he has a 6MT, is light on the skinny, and shifts low. I do that in traffic and get great economy. It's hard to get phenomenal economy on the highway though without putting along exactly at or under the speed-limit. It seems to me that average highway cruising of 75 or so MPH yields approximately 23-24 MPG on a generally flat grade with a well manicured road and a nicely maintained G 6MT.

 

If you have an android phone go download the "torque" app, (theres a free version) and then go to eBay and purchase an obdii Bluetooth scanner. Link the 2 up and you can run an average miles per gallon test to get real time numbers. I did this last week on my 05 coupe just for fun during a short 40 mile trip and averaged 38 miles per gallon (majority interstate driving, but a few city miles) when the trip was over, but at times was well into the upper 40's. I also have made trips with my wife in which I put close to 450 miles onto 3/4 of a tank of gas. In neither situation Was I doing anything too crazy to try to save fuel. I live in a flat state, and didn't rev the **** out of the motor. I use premium fuel, stay up to date on my maintenance, keep tire pressure where it should be, and in general just drive smart. Typically I average around 350 miles per tank, but I usually fill up when I'm half empty anyways. Regardless, its not impossible to get MUCH better then advertised fuel numbers with consistent smart driving. Go get the app and try it yourself.

 

And then you realized you were in your civic^ 38/upper 40smpg?!?!...gitreel homeboi

 

19 city isn't unrealistic. i know highway i get about 25-26 mpg usually. so i could see if you baby it through the city that you'd get good mpg's

 

^yeah, just cuz you can get 40mpg going 60 on a downward slope doesn't mean your avg is anywhere near that. Otherwise I can claim 99.9mpg cuz I get that (or more) when I put it in neutral down hills.

 

You are wright I change at city at around 3000rpm and we have speed limit at city 35mph, but some areas at city are allowed 50mph, where I drive also often and city traffic at morning is not so overcrowded. So that helps a lot. By the way at our city police traffic patrols have been also very keen to make you ticket in every possible way, so it is rather difficult to speed at center.
And at highway our speed limit is 55mph basicaly and some places 75mph.
So when drive economically at highway is 29mph highly realistic.
At city 18.7 is mine figure and my best is 19mph.You do not need take off rapidly in every corner, by the way,G35 engine is rather strong and torque is enough is middle rpm, so it is wise take that advantage to everyday driving if possible.
When it is possible to drive in steady speed in 5 th gear I use it immediately.
Nevertheless they do not suggest I have heard use 5th gear below 40 mph.
So it is not so difficult .
My constant city fuel consumption is 18.5-19 in city.
It is not so difficult to drive economically in city if you want save in fuel costs having still powerful car and take off rapidly any time. There is not need to do it always.
Here my fuel price is rather high also.3.52USD gal.
In USA you have advantage where gal. costs only 0.7 -1 USD. That is very cheap.
But I want to draw out general law. 6MT is always economical than aut.
It is possible that new Q50 7 speed aut is most economical of when compare to G35 or G37.But Q50 is too new and rather pricey also.

 

I have an 04 sedan, 160K miles, and original spark plugs. Highway mileage down to 21.3 mpg. Ordered replacement plugs and plan to change them this weekend, along with oil/filter, air filter, and drain/fill auto tranny. Hope to get to 25 mpg after all that.

 

Now we're getting somewhere.

 

I need new plugs too. I am just really dreading this idea that I might have to remove the upper plenum assembly to get to my spark plugs...

 

My 2006 G35x says to not use SNOW mode on dry roads

 

You don't. You just have to remove all those brackets around the plenum that hold down that bundle of wires. It's easy, but tedious. There's a really cool YouTube how to.

 

160k and original plugs?!?! Wow. You're gonna pick up a LOT of hp when you change those. Is it the original air filter too? Jesus..

 

OK, here is what I did.: I had my spark advance reprogramed on computor program...added 2 degrees initial and REMOVED 2 degrees on top end...
what this does is provide more inital spark earlier but still remains the same on top end which is still optimum...always make sure you are running some 32 lbs of air COLD in all tires. the car has a performance paper air cleaner with drilled holes thru the air cleaner (front) to match drilled holes in front sheet metal cross member to (MATCH) holes drilled in air cleaner. this actually helped a bit in power and gas mileage...in stock form with 89 octane. (I have run 93 for many months when first purchased car but find it does nothing. Hi octane burns/ignites slower to forgo the ping...my car went from 27.2 to 27.4 mpg (Turnpike 65mph) while being noticibly faster on slow to middle range
and last most folks do not calculate mpg correctly. what one should do is FILL tank completely, note mileage at start. run car some 100 miles, stop fill tank and note how many actual miles driven divide by AMOUNT of NEW fuel.
this car is stock except for the Z tube which enhanced the sound and nothing more...this is one great car Nissan has provided us car nutz

 

^I dunno what this guys talkin about.

You wanna increase.mileage? Make it easier for the engine to breathe, make sure your maintenance is kept up and make sure you have as little rolling resistance as possible (my tires are at 50psi) (get rid of extra weight), and don't stomp on the gas. That's it. There's no secret; pretty common sense stuff.