I have a 09 G37-S 7AT. I've had the car since September 09. For the first 3700 miles, the fuel economy was around 23.5 to 24 mpg. After my first oil change, the fuel economy went straight into the toilet and now I'm lucky if I get 21 mpg. My driving habits have not changed and I drive the same route everyday. I don't know if the car came factory filled with Nissan's Ester Oil, but the dealership put conventional 5W30 in when the oil was changed. Could this be the issue? If so, then for fuel economy purposes alone, the Ester Oil might be worth the $90 price tag.

Has anyone else also experienced this?

 

Not sure where you live, but did the weather turn colder? That will often make a significant difference in gas mileage. I think that until the engine completely warms up, it uses more fuel.

 

TTBoy, Nissan Ester became the factory fill after mid model year 08.

 

I agree with hi alt g, the cold weather might be the cause of this.

 

Hmm...my 09 made the cold start clacking right from the get go. You sure it was filled with ester oil? My next two oil changes were good old 5w30...and i can't tell a difference in the cold start up sound.

 

I have a 6 speed MT, and I've been averaging 19-21 mpg in mixed driving; I use Ester oil exclusively.

 

No kidding... since winter started, I'm lucky to keep my 09 G37x above 16mpg (all city/suburbs, very little highway).

 

A lot of places start selling Ethanol based gas in the colder months, this will really ruin your mpg. I typically get 30 mpg hwy but w/ ethanol I get around 26. Now I make sure to avoid any Ethanol stations and I'm happily getting 30 again

 

I just recently got my g37x and I'm getting around 15-18mpg..... is this average?

 

I blame the ester oil... ha

I'm going to put full synthetic in my car at my next change (in a couple days) and see if it gets better. This is really the only change that's happen since my mileage started to really suck... I'm getting about 16.4 mpg... on avg... maybe 18 when it's a lot of highway.

but yeah I mean the smart person would put their money on "winter" gas. or gas stations that are putting the up to 10% ethanol in their gas.

 

I have a 09 37xS sedan and I average 20 commuting to work and 26-30 on the highway. I have noticed that since I put SRI intakes on the car, the gas milage has decreased 1-2 mpgs, but I might be driving it a little harder, just to hear the sound.

 

I think winter fuel blends is your problem with mileage. I've been using synthetic oil since 4K miles and now have 17K, but that didn't change my mileage. The only thing that has changed mine a bit is getting the 7AT tranny TSB done months ago. The best I've seen prior to the flash was 30 mpg all highway. I should have left well enough alone and lived with the hard 4 to 3 downshift. I now average about 26 with 80% hwy driving.

 

09' G37S 7AT here. Had Ester for my first oil change, standard synthetic the last two. Personally liked the Ester more.

Anyway, I live in the DC area but have family in Upstate NY. I get around 16-18 in traffic, but averaged 26.7 on the 300mi trip to NY today.

 

That's good to know (not good for you, but good for me ) I was contemplating having the trans TSB performed, but I'll deal w/ the minor annoyances, maybe they'll come up w/ a better fix down the road that won't gouge the mpg so much. FWIW, the trans shifting issue doesn't seem so bad now that I've got over 5k on the G, either I've just gotten numb to the quirks or the trans has actually smoothed out somewhat, probably a combo of both. At any rate, I'm still liking it quite a bit better than our 07 G35.

 

how are people getting 20+ mpg? how do you drive your g? you barely step on pedal?