I have a 2010 G37xs since last february and have recently seen my mpg go down significantly.

Last winter it was bad because the car was in the process of being broken in . Now I have a shy over 10k on the odometer.

Every since maybe a month or two since temperature dropped my avg mpg went from like 19, 20 to nearly 15mpg.

Any ideas to this? is it the cold weather? or maybe wrong oil change for the weather?

I am in NJ and the temp around here is in the 30s now.

All input will be appreciated.

 

try changing up the "brand" of gas you put in (switching from chevron to shell during colder climates yield ~400 miles per tank, for me anyways versus the 320 I get with chevron, again during colder weather). gasoline mixes tend to change during the winter...more of some sort of additive. if my memory serves me correctly (albeit it doesn't sound right now that i think about it), a/f ratio are opposites. when you get more air (colder air = more dense air, therefore more per give size intake) means fuel goes down? worse gas mileage? k, i have no idea what i'm talking about. but the winter mix gasoline still stands...lol sorry i couldn't be of more help...

 

My MPG used to be around 16 to 18 before the winter. I'm now getting 13 to 16 in the winter. The car seem to use much more gas in cold temp.

 

don't use wawa gas. They put cheap additives to meet minimum standards. Use ones like Lukoil or Shell, they are more invested in better gas additives. I get 20.4 mpg using Lukoil. You just gotta try and try until u find your favorite one.

 

You shouldn't see that much drop in mpg. Mine drops from 22 to 21 in winter. Are your tires properly inflated? Also, don't spend too much time warming up the engine. I just let it run for 15 seconds on startup.

 

I am currently getting 20.6 mpg according to the screen's avg mpg calculator on a 6mt tranny

I fill up with chevron

I believe elevation could take part in this so... I am in South East Texas

Temp in the morning is roughly 45F temp in afternoon is around 63F... Super cold for down here, almost forgot how to use the heater on everything.

 

i'm a shade over 20mpg for city driving, 6MT. this is for a milder west-coast winter where average temps are ~0C (32F). my gas light just came on and i'm at 325 miles. i just bought the car in november so i'm not sure how this compares to summer driving.

check your tires, air pressure drops in the cold...

 

Seasonal changes that impact fuel economy:
1)Winter fuel mix vs. summer fuel mix (Small change) Changes are across all brands for smog reduction(summer) and vehicle performance(keeping the vapor point and other properties in a manageable range to keep ICEs happy.)
2)Tire inflation pressures- Max operating pressure will change as max operating temperature changes. I saw better gas mileage during our 100+ summer than during the time it was in the 80s and 90s(same fuel formulation). Tire pressure was about +2 psi higher according to my TSX TPMI. This would be an even bigger effect in the winter time. Check your tire pressure.
3)Defrost time- If you park outside, you may not be able to just hop in and drive off. knocking the ice off the windows while the car is idling will eat up the gas.

Air conditioning will have a variable effect during all seasons in most places. It runs during the cold to keep the windows unfogged and in the summer to keep it cool. It could be argued that it would have a slightly more negative impact during the summer as it would run continually.

Rotating fuel brands periodically is a good idea. The base gasoline is all the same, with different additive packages from each retailer. The fuel from one brand will clean the deposits that the others don't and vice versa. It is best to stick to the top tier gasolines.

 

My car is in the heated garage most of the time. I usually give it about 30 seconds before I pull out. But when I cold start outside, I give it about a minute.

All tires are are perfectly 33 PSI, so I don't think that's the cause of lower MPG.

 

Stop drifting the snow filled empty parking lots for hours at a time and you're MPG will return to normal

 

Scratch my last post, just checked my car and this is my real MPG

 

Do you drive mostly on highway?

 

Ethanol is the most likely culprit, at least it is around here. I get about 10-15% poorer fuel economy w/ Ethanol. I just fill up locally at Sams Club since they NEVER use Ethanol.

 

gdamn it I get like 16.9 mpg... even in the summer. what the heck... at most 17.5 with 50% highways. I can't even try to get better mpg... no matter how soft i drive it.

damn it infiniti, expect a call from me.

 

I typically get better mpgs in winter. But not in the G.