10mpg in the city....whats wrong with my car?

[WhiteyClay]

Ok here are 2 questions1st. How big is the tank on 03 sedan?and 2nd is...I got some mods in my car (mrev2, spacer, pulleys, exhaust,intake, ztube)I live in the city.I tired it twice already and i do 190-200 miles on a tank.What can I do?I do like to press the gas a little but i dont think this is ithelp me out guys

[zozoka1212]

I always get 13-14 mpg with pure city driving. My wife was using the g for a week and she's got lot better. I know how she drives. I don't think anything wrong with your car. It is just if you pass 2k rpm in city and you use brake and gas only, you'll have a crapy mpg. Try to change your driving habit for a week and see the changes. I get 350km out of my car. My wife got 600km. The tank wasn't even empty!

zozo

[Andy_V35Sky_350GT]

Yup, driving style is a big factor.

I get on average about 450km a tank with mixed driving. I once got over 800km on a single tank with continuous highway driving.

[telcoman]

Ok here are 2 questions1st. How big is the tank on 03 sedan?and 2nd is...I got some mods in my car (mrev2, spacer, pulleys, exhaust,intake, ztube)I live in the city.I tired it twice already and i do 190-200 miles on a tank.What can I do?I do like to press the gas a little but i dont think this is ithelp me out guys

I think living in Queens is the problem? I used to live in Kew Gardens and moved to New Jersey. I had a lot of problems with my 1958 Ford back then. Perhaps your vehicle has some steel from it?

Make sure your tires are inflated to 35lbs when cold and your Air filter is clean.Sitting in traffic, idling for long periods, lots of engine restarts, short trips, engine not reaching normal operating temperature, humidity, air temperture are all factors that will reduce your MPG.Have you ever driven on a long trip (400-500 miles) on mostly cruise control with the windows closed & using A/C? If not try that and compare. I get close to 28 MPG on the road. From reading many posts it is also possible that the 03's get lower MPG?

Telcoman

[rn79870]

What do you mean by "city." Is it stop and creep driving, or do you actually make progress albeit slowly. My G gets predominately city driving, but it is the kind of driving where you are going 0 to 40, stop, 0-40 stop. The dash reports that I average 16.5 to 16.9 in town, but that is accelerating rather easily. If you are in stop and go traffic, with a lot of stand still idling, then I'd say 10 was good.

[TeflonG35]

I'm pretty sure the tank is 20 gallons.

[1njen]

The tank of my G is 20 Gal and the empty light comes up when you have 5 Gals left. If yours is an automatic, thennn it should be getting 18x15=270. I guess if its bad stop-and-go traffic you could hit 200. ionno. hope that helps.

[BrandAidDesignG35]

I have an 2004 sedan AT, I can get 20 or less mpg in 50% city 50%hwy mixed driving conditions... safe to say I get above 16mpg in the city.

I think the most I ever got on a tank was 650 km, however, the light will generally come on around 450 - 500, but I have a really heavy foot, so this seems to be on par with others.... I would check your plugs and air filter ASAP

I found that with the new exhaust system and intake, my mpg is improved by around 100 km per tank and I think my foot just got heavier also

[mrsmithGrider]

I would say with a light foot I get around 20 mpg mixed highway and city. With moderately spirited driving I get around 16 or 17 mpg and when I first got my car, for the entire first year I could get no better than 14 mpg because of full throttle driving. Right now, I have 200 miles on my current tank of gas with a little less than a half of tank left!

[WhiteyClay]

ok so its not just me then...lately i drove on a highway with ac on and did 60 miles and needle hardly moved...guess need to take that brick off my foot.thanks guys

[G_whizz]

I consistantly average 400km per tank. Mostly all city driving.. and I drive "spirited"

[telcoman]

The dash reports that I average 16.5 to 16.9 in town,

rn79870

Faaget about what the dash reports!

The only ACCURATE way to calculate MPG is to fill tank. Set odomenter A to zero. Refill tank at 1/4 mark or below. Divide the gallons it took to refill into the number of miles traveled. This is the only accurate way to calculate miles per gallon.

Telcoman

[Sentientbydesign]

rn79870

Faaget about what the dash reports!

The only ACCURATE way to calculate MPG is to fill tank. Set odomenter A to zero. Refill tank at 1/4 mark or below. Divide the gallons it took to refill into the number of miles traveled. This is the only accurate way to calculate miles per gallon.

Telcoman

Very true. I had an 07 5AT sedan Thursday and Friday and the Dash fluctuated so much, it was comical.

I started the car in the driveway and it said I had 21 miles till empty, I drove less than a mile with light/moderate acceleration and it said I only had 16 miles till empty.

Drove another half mile (partially downhill) and it said I had 23 miles till empty.

What really blows my mind is that under acceleration, the MPG will drop below 10. Jacko claims that his never goes below 2x with WOT.

I drive around 25-300 miles per weekend in the city. I basically make the same 8 mile loop over and over again checking on my employees. If I drive normal, I get around 16-16.5 MPG. If I drive conservatively (ie, shifting at or before 3k RPMs, smooth/light acceleration). I get just over 19 MPG.

HWY driving at 80 with a few passes here and there yield me low 20s.

Do a search for "Ways to improve fuel economy" and you'll see my write up on things that affect your MPG and what you can do about them.

[smockers83]

In the city, I consistently get around 17 MPG, give or take 1 (usually take). On the freeway I can get from 24.5-26 MPG. I do have an oddity though. I always get around 24.5 going north and around 26 going south...I use 93 going north, 91 going south. I must be goin up hill when headin north.

My last trip, I recorded 24.55 MPG over 545.3 miles (22.209 gallons of 93) with a slowest maintained speed of 65 and fastest maintained speed of 85 (maintained = over an hour). Tomorrow I head south to complete the road trip.

[Tampa G35 Sedan 6MT]

My last fill up i got 26.33 and i have gotten over 30mpg on the Highway at 75 before.

590miles on one tank.... from very full to bone dry! I put 19.3 gallons in the tank MPG 30.7

It can be done but you have to try really hard. I try when on road trips. But other than when on road trips... I drive the G balls to the wall!

DJ

[lomita]

We get 12mpg city consistently (21000 miles so far). So, pulled the plugs, only to discover now the seals are leaking in the spark plug tubes and you can't replace just the seals, have to replace the entire valve cover ($221 retail). No problem, we're still under warranty. Just screws me out of my time to take the vehicle in to the dealer and pick it up.

I am beginning to get a real bad impression of the quality control, there doesn't seem to be much quality control in the production of these vehicles. Some of these cars get great mpg and some don't. It is beginning to appear the engineering has suffered.

We will not ever buy one of these sleds again. OH, did I just ventilate. EXCUSE ME! I feel better now.

[Sentientbydesign]

I'll be the first to admit that the G35s have some unique issues, but overall Infiniti has built great cars. My last one is probably tipping 280k miles right now (I sold it a couple months ago).

I think the biggest problems with the Gs are the consumer demand. Infiniti sells way too many of our cars. I personally think they are used to doing smaller production and therefore have better quality control.

Their new emphasis on performance may have something to do with it too. I'd still buy another Infiniti over ANY American car or Korean car.
Modified by Sentientbydesign at 10:48 AM 5/19/2008

[lomita]

The Nippondenso Long Life Iridium plugs have made a difference for us in our gas mileage on the road. Checking mpg around town on the next load of fuel.

[Q45tech]

300HP consumes 150 pounds per hour or 24 gallons of gasoline per hour, that's 0.4 gallons per minute................plus the A/F ratio is extra rich in acceleration so the actual consumption would be closer to 0.6 gallons per minute.

[lomita]

Is there an aftermarket flowmeter/indicator we can install on our 05?

[Q45tech]

Actually the returnless fuel system makes it easy but very expensive to acquire an accurate reliable unit.

Why not use data log software and count up the injector open time [in 0.00 millisecs per minute, hour etc. if you want pounds per hour then divide into miles covered........................roughly what the built in MPG meter does.

The eror comes in when you need to adjust gasoline for temperature and density.

Good luck in beating factory engineers.

[Kenrik]

I get 20mpg driving it like a granny and 18mpg flogging it to 7k rpm from each stop light..

IDK why there is such a small difference.

[Q45tech]

Difficult to get worse than 6 mpg even holding steady at 145 mph.

But in the 60 seconds it takes to reach terminal speed you can burn ~ 1/2 gallon covering 2 miles.

[Sentientbydesign]

Q,

Could you please email me. I have a question regarding the proper cleaning procedure for the DBW throttle.

Thanks,

Nate

[InfinitiG35driver]

take out your mods / run stock! you will get better gas milage! Sucks, but something has to give!!

[CPV35GT]

Try cleaning your MAF. Might help.

[lomita]

Our MAF sensor was clean as a whistle, hence not the problem for the same low gas mileage condition. Suspecting ECU related, some sort of dash number difference, i.e., a good lot and the lot that sucks gas mileage out of the car. A few of us unfortunates..............