kdawg8526

iTrader: (2)

need help bad. i got a 2011 g37s 7at rwd all stock with stock 18" wheels. i am getting 9mpg 100% city driving. i have changed oil/filter and air filters. i have also run seafoam thru the intake manifold and fuel tank. i always put 92 octane from shell. i know that this car isnt that great on gas but seriously 9 mpg is ridiculous and i dont drive like a old man but i dont floor it everywhere i go i generally keep the rpms under 3000rpm while normal driving.

the computer is telling me im getting 14mpg but thru my own calculations im getting 9 mpg 150 miles to a tank before light comes on

i dont want this to turn into a mpg feedback thread. please help on what should i do. should i go to the dealership and complain?

(a couple months ago the dealership did update the ecm and i noticed after that it has been getting lil less fuel economy)

ashmostro

iTrader: (3)

Yes, take it to the dealership. That's so bad that I would expect them to want to look into it.

telcoman

Before complaining/going to the dealer fill the tank. Take a trip on the freeway for 300 miles on cruise control at 65 to 75 MPH until your fuel gauge is down to the 1/4 tank mark. Refill the tank and divide the miles you just traveled by the number of gallons it took to refill the tank.
Post your results. I am sure you will be surprised at the results.
Try it a second time with regular 87 octane. You may be surprised again.

Photo taken after a fillup with regular 87 octane after a 50 miles drive to work at 65MPH on cruise control.





Telcoman

ashmostro

iTrader: (3)

What would that prove other than freeway mileage is way better on our cars than city, which is definitely the case?

I'm assuming the OP knows how to measure MPG correctly. If so, 9 mpg is far beyond any typical error rate in measurement that it should warrant getting checked out. If the OP said 15 mpg, I'd be singing the same tune as you.

Black Betty

iTrader: (60)

What is the total number of miles that you drove? Exactly how many gallons of fuel were used to drive this distance? The light coming on has nothing to do with anything.

owslystnly

Why do you use 87?

rpm&my_G35

There are way to many variables why one persons fuel mileage would be better or worse than another's.

If you are convinced that it is truly 9MPG then it warrants a trip to the shop. I hope that's not 9 miles per Imperial gallon because that makes it even worse. So bad that I would say you have a leak or someone is stealing your gas.

Ibanez540r

iTrader: (1)

I think everyone's definition of city driving is different. To me, it's suburban driving on 35mph roads with a light every few minutes. To others, it's dead stopped traffic, getting up to 10-15mph before hitting another light or stopping in traffic. So, if he's truly inner city traffic 100%, then I don't think 9 mpg is too far fetched. Sucks though..

I think Telcoman's point was to see if he gets normal highway MPG which would lean toward the car being normal, and it is just his conditions. ..If he was to only get 18mpg highway, then it would clearly indicate an issue with the car.

Also, how many miles are on your car?

blazeplacid

iTrader: (1)

I would take it to the dealer if under warranty

I would be pretty upset refilling my tank ever 150 miles

stanv

I had 11MPG & went to the dealership...they did something and now I have 14.1 MPG....I was hype as can be lol. At least 80% of it city driving & I live in NYC...so that's amazing lol.

Tazicon

iTrader: (1)

TAKE IT IN UNDER WARRANTY! Why are you coming on here wasting time, take it in find out what the problem is.


Or you could try this, before starting the car, lightly tap the brake peddle 3 times, then the gas paddle twice, wait 5 seconds then turn your left blinker on for 10 seconds, then swicth to the right for 10 seconds. After this start your car and all will be fine.

telcoman

Because I've proved that using 93 octane for one month with my 06 G35 and 91 octane for another month was a waste of money providing neither improved performance or improved MPG.

My G37S was delivered to me by the dealer with a full tank of regular 87 octane. That is what I've used ever since I took delivery and I'm satisfied with both performance and MPG.

I know what is in the owners manual and I know what is written on the gas flap. This is to meet HP specs which mean nothing to me.

On my recently traded 06 G35 I used 7179.324 gallons of mostly regular 87 octane except for the two month premium test periods over 171431 miles at my final fill up for an overall 23.908 MPG over an almost 7 year period.

Frequent short trips, stops and starts kill MPG.
Long trips on cruise control produce reasonable MPG for such a powerful engine.

Telcoman

hinomura

iTrader: (4)

Taz, maybe he should try UP, UP, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, B, A, B, A, START when he starts the car up? I'm pretty sure he'll get at least 30 <strike> lives</strike> mpg right?

ashmostro

iTrader: (3)

^^^Yeah, true. That puts the ECU into contra mode. Fixes the AFR across the powerband.

owslystnly

Just FYI, commuting to work (80%hwy, 20% suburban) I get 25-26mpg, on all highway trips, 28mpg using 91-93 octane. It's only an extra ~$50-100 or so for the year, so.......be cheap if you want to.

And I get better mileage NOT using cruise control. After driving a civic w/o it for 10 yrs and learning to drive to get 50-60mpg, your foot and brain can do better than CC.