Winter Gas Mileage

I asked my Honda Service crew why my gas mileage on my 2008 CRV has dropped drastically.

I was getting up to 33 mpg on long road trips; about 27-28 on short hops. Now I get only 22-23 MPG. The crew suggested it is because of additives in gasoline - the winter mix, they called it.

I have kept the maintenance schedule faithfully, and I drive the speed limit or below at all times.I have 4 new Goodyear tires - ones that supposedly improve gas mileage.

I have never heard of additives causing lower gas mileage in winter months. Have you? Would you attribute the mileage change to this reason - or to something else?

Please share your ideas!

I think the service crew is right. Gasoline is blended differently in the winter for quicker start-up. This will lower the gasoline mileage. Furthermore, the fuel/air mixture is set richer by the car’s computer in the winter while the car is warming up to improve driveability. This uses more gasoline. In the days of the carburetor, we had a choke which was a damper that cut down the air going to the carburetor and enriched the mixture. In later years, cars had a thermostatic spring that opened the choke. In the good old days before the automatic choke, the driver had a choke control to do the same thing. There is nothing wrong with your Honda.

Triedaq: Thanks so much for your clear explanation. (Are you a mechanic or an automotive expert of some sort?) I will keep my eyes on the road, and not on the gas mileage gauge. Your reply is helpful - and reassuring!

In many places gasoline formulation is indeed different in winter; and it generally does result in diminished fuel efficiency. But just the fact of cold conditions also works to cause mileage to dip. Some people start the car and let it idle until the heater can melt crayons. This is bad for the engine, the environment and fuel mileage, if nice on the toes. Even without excess warm-up, modern cars with electronic fuel injection and even those intermediates with an automatic carburetor choke work less efficiently during those parts of the drive cycle when the engine is not up to temperature. Basically, the amount of liquid fuel in proportion to air used by the engine is increased to get the thing to run at all, and more of it is spit out the tailpipe without contributing its energy to moving the car.

My old Jeep stays parked most of the winter up here in the Rockies because the roads to the good places are too snowed-in for wheeled travel until about June. My other car, a 20-year-old Miata, gets around 40 MPG in summer and maybe 36 MPG in winter (figures at sea level might be 20% less). Gasoline up here doesn’t vary by season, so I’d guess that maybe half that 10% variation is from the reality of operating in cold conditions and the other half because I just enjoy blasting around on smooth, snowy roads more than clunking along rough dirt paths.


In most parts of the US, if not all there is a change in the gasoline mix during the winter. It is due to an effort to reduce pollution and to some extend reduce condensation from collecting in the tank. They blend in ethanol which has less energy per gallon so you get less mileage. Nothing wrong with the car.

Thank you for the compliment, but I’m neither a mechanic nor an automotive expert. We didn’t have a lot of money when I was growing up, so we had to learn to do a lot of things for ourselves. We learned how to maintain the car, do wiring and plumbing, etc. All of this really paid off when I had my own family.

Yes, additives in the gasoline might reduce your fuel economy, but the gasoline is also denser (since it’s colder), so there’s more energy per gallon all else being equal (which it isn’t, but it does mean the drop isn’t as bad as it might be). Also, when you first start the car, it’s probably running rich, and less efficiently in general. This won’t last long, minutes or maybe seconds, but that’s just another thing conspiring to make your fuel economy worse.

But the biggest drop is probably from changes in your driving. If you’re letting it idle, that’s 0 mpg right there. If you’re spinning your tires at all getting started moving on slick surfaces, that hurts your fuel economy. If you’re driving or accelerating too slowly, that could also be hurting your fuel economy.

The way to get the best winter fuel economy:
Idle as little as is safe for the car. If you’re just below freezing, that means MAYBE a minute or so when you first get going, and not at all after that if you aren’t stopping anywhere more than an hour or so.

When accelerating on snow and ice, do so just below the limit of your car’s ability to maintain traction. Give it just enough gas so that if you gave it any more your wheels would spin. Wheels spinning is wasted fuel and wasted time.

Braking, you should be a good bit farther below the threshold for slipping than for accelerating. Another thing to do is try to time your braking so that you don’t have to stop at red lights…that is, get to the light just as it turns green. Doesn’t work in heavy traffic, but this technique gets more noticeable results in winter than in summer.

Make sure your tires are properly inflated. When it gets cold, your tire pressure drops, and the tires get softer (well, after they’ve warmed up, they’re softer than they’d otherwise be). This can be good for your traction on snow, BTW, but you don’t want the pressure to be too low regardless, and it will never help your fuel economy. Any time the weather warms up or cools off significantly (say 20 or 30 degrees) you should check your tire pressure.

Oh, and driving the speed limit isn’t necessarily going to help you. First of all, the optimum cruising speed for some cars is higher than a lot of highway speed limits. (My 96 T-bird got its best highway economy at about 70 mph) Second, it’s far more important how you get to that speed than whether you’re a few miles per hour over it. Accelerating is when you burn the most fuel.

On top of all the stuff others mentioned cold air is more dense, which increases aerodynamic drag.
So even a warmed up engine consuming “summer” gas will use more fuel cruising down a cold highway.

Are you sure you were measuring right before? 33mpg would be incredible for this car, even if it’s a 2wd and even if it is all 55mph driving.

Yes,Greasy Jack, I am positive - and I was as surprised as you are when it first happened. I get 33 mpg mileage repeatedly on a 6-hour drive to Washington D.C. through the Pennsylvania mountains. I also get 33 mpg on regular runs from my country home in rural NY to the nearest store, 15 miles north.

Any suggestions on how I can keep it up?