I am new to the forum and new to the G35 sedan. I recently purchased a 2003.5 G35 sedan auto 16,000 mi. I seem to be getting bad gas mileage compared to others on this board(I did search). My first tank got just under 18 mpg 50/50 city freeway with a heavy foot. On my second tank i only got 15.8 mpg very easy on the gas 50/50 city freeway. i am running 18in coupe rims but that should not do much...

Any ideas? Maybe change oil or reset ecu? TIA

 

to me, those figures don't seem to be out of the ballpark. i'd recommend you take an average over about 5 tanks before getting too alarmed.

 

thats actually pretty good. i'm 17 with a 05 G and i'm just so happy with it, the way i drive i have to fill up 2-3 times a week, lol. i pay like 50 bucks a tank man ( damn 91 so expensive here in cali ). my worst miles per tank was I believe 200. i actually tried driving slow and like a grandma and i only got about 270 per tank. 70 miles isn't really that much to me, it might mean alot to someone else. that 70 miles aint worth missing out on all the fun I have the way i normally drive

 

Ive had my 05 for about 4 month now and Im avg'ing about 17 mpg.

Most of my mileage is city driving and I mash the gas pedal from time to time, so I think its pretty darn good considering the thirsty engine we all have.

 

The mpg i have gotten has been based on driving it like an old ladie to see how many miles i can get out of it... but im to the point of saying eff it and just havin a ball

 

The 25 year old EPA gas mileage test proceedures are extreme, much better than any old lady could acheive...........computer road simulation [dyno] with no wind resistance.

Highway maximum of 61 mph peak average 55 mph no AC in operation. NEVER NEVER NEVER a WOT acceleration.
They bare little resemblence to how modern sporty cars are driven!

All cars are optimized for 55 mph to get better numbers on these test [and pay smaller taxes to government] and as a result may suffer if driven much over 60 mph.

Kind of like everyone enjoys fooling themselves into still believing EPA numbers are even close to valid under today driving speeds.

 

I got my 05 g35X back in january and the first tank was something like 18 or maybe 19 combined. The mileage in the dead of winter was 21 combined about serveral tanks. I get 23 combined (70/30) all the time. I am not much of a lead foot but I see 80 every am on the way to work and I drive more on the agressive side.

 

I just got back from a vaction and I got 18.8 mpg 455 mile round trip w/air on and the car loaded with wife daughter and trunk full of sheit. My car is a 04 g35x not bad for 70-85 mph!

 

Ditto - I am right around 22 MPG with the occasional tank in the crapper when I lose control of my right foot.

 

Things to consider if you're getting bad mpgs:

1) Is it hilly where you live?
2) Do you get stuck in a lot of rush hour traffic?
3) Do you do a lot of short drives (less than 5 miles)?
4) Are the tires at proper inflation?
5) Do you do a lot of jack-rabbit starts from the light (it's really easy to do with the 5AT)?
6) What octane? 91+ is needed. Nothing less. The VQ35 operates way too close to the knock threshold. If you run too low of an octane, the ECU will pull timing and add fuel to cool the combustion chamber. This will hurt your MPGs.
7) Have you considered changing fuel brands?

The 18" coupe wheels will impact MPGs. They weigh about 7lbs more overall than the 17" rims. Factor in a 1" larger rim with more weight further from the hub and it's easly to see why MPGs will drop. I would think the 18s are probably sucking out 1mpg and maybe even 2mpg. I know that on my 96 Maxima, I would get 2mpg less when I'd be running my lightweight 17s (40lbs) vs running my OEM 15" rims (42lbs).

I always seem to get 18mpgs in 80 city/20 highway driving. I drive fairly hard too. I've never done a full highway tank, but I have gotten has high was 22mpg in 30 city/70 highway driving with my wife and baby on board.

 

I am averaging about 17-18 mpg but I do mostly city driving on my 05 auto.

 

My AT gets 17 - 17.8 on avg... I do a lot of city driving and even in So Cal hwy driving is almost always stop and go. The best mpg I see is on longer road trips where I usually get 19+ mpg. I drive very spirited frequently!

I think the only ones getting in the 20+ range are MT... most AT are probably 17-18.

I was a little discouraged at first, thinking the mileage would be better, but with the mods I’ve done and increased HP I’m satisfied with the mpg vs. performance. Fortunately I haven’t lost any mpg with the mods.

 

You mileage isn't that bad bro....If your oil is dirty and due for a change, you might get a tad more afte changing it out.

To get any decent mileage out of it, you must do steady speed (no more than 60) and no fun whatsoever.
Any kind of fun and higher speeds cost big time.
C.

 

I guess im not doing too bad. I will change the oil and see if it helps. I do run 91 octane usually cheveron. The bigger wheels should not be doing much, I know the stock 17s are and inch or so smaller but wouldnt the 18s on low profile tires be about the same diameter?

 

shiiiiiiiiiiiiiiiiiite! I'd be ecstatic if I pulled 17.

I'm averaging 11-12, and that's with staying below 4000 rpms. I only have 300 miles on her, so I'm hoping it gets better after an oil change around 600 to get all the sh*t out.