OK, ever since the colder air set in here in New England
I'm getting 50 miles less per tank full .
The difference in use on my end is having the heat on in
Auto mode set to 68 with no A/C on. It hasn't been that cold that I have had to go start her up and let her sit there to warm up.
I know they add a additive to the fuel in the winter just not sure what
that does to fuel economy. Anyone have any ideas ?
Can't believe using the heat causes this much loss.

Ralph

 

It's not using the heat IMO, it's just the colder weather and the gas additive, so far this year, I seem to be maintaining similar mileage per fill up, we'll see!

 

Shouldn't colder temperatures make the car more efficient in that it is sucking in very cold air into the engine instead of hot air like in the summer?

 

All the cars I have owned consumed more gas during the winter. I assumed the engine has to work harder in the cold. I doubt it is the gas giving worse milage. The past 2 fill ups on my G35 were getting about 40 miles less. I also put winter tires on and not sure if that affects milage.

 

Offhand, I would think that colder temps would result in thicker oil and grease consistencies, so that would also be detrimental to fuel economy. But I would think that effect would disappear as the oil and grease comes up to temp. Just another possible thought...

From my layman's point of view... An intake of colder air would help to create a denser charge in the cylinder. However, if the engine block itself was too cold [in this case due to ambient temperature?], then there could be some inefficiency of the detonation / complete burning of the charge. Hence, a loss of fuel efficiency. But once again, I would think that the negative effect would be relatively short lived as the engine block comes up to temp. Oh well, just another thought...

 

It's quite normal for engines to burn more gas in the winter due to warm up time.
The additives in the gas will affect mileage too.

I've noticed our VQ engines are worse than others for poor mileage in cold weather. It's the nature of the beast.
Sucks, but that's the way it is.

I preheat mine with the block heater for an hour or 2 to help with this issue.

 

In the winter months they switch to oxygenated gas and the results is less gas mileage.



Gas mileage and oxygenated gas

 

I notice that the traffic is a lot worse this time of year. That really takes its toll on gas mileage. Just a thought.

 

That's for sure, my last fillup, after driving about 50/50, was around 22mpg, and the city driving was a lot of stop and go crap, in that mix, I usually get around 24-25 mpg!