Reduced gas milage with colder weather

I own a 2008 Tacoma TRD Doublecab, V6, 2wd, auto trans. I have been noticing my gas milage dropping with the cooler weather. I have read that with cooler weather some gasoline uses more ethanol which I have heard can drop gas milage. I run mostly Shell 87 ocatne gasoline that supposedly does not contain Ethanol (??). I never run higher octane because my owners manual specifically reccommends the 87 octane. Anyway, our temps here in northern Alabama don't get so cold as say up north but cold is cold. Is anyone else experiencing a drop in gas milage with the cooler weather?

 

Its to be expected. I live in MA, and in the winter you can watch the gas gauge drop.

 

Gas mileage will drop from driving on snow and running the heater, but if your not doing that in Alabama you wouldn't think it would make a difference

 

mileage is gonna drop a bit in winter for a few reasons...running heaters will do it, but also the gas additives...or lack there of will cause it as well.

 

Do you let your truck idle for a while to warm up?(more than you normally do) I know I am burning a lot of gas just warming the truck up. Of course it is a lot colder here.

 

I know gas mileage can and will go down some during colder weather but I find the amount I'm losing right now to be a tad much. We have had several pretty chilly days but nothing significant. We have had several days with temps near freezing but never below freezing. I don't run my truck to warm it up and I don't drive it hard. I may get a little heavy on the gas now and then but thats the exception rather that the rule. I have my truck serviced regularly and my dealer uses the oil best suited for our area and weather conditions (usually 5W-30 for cooler weather and 10W-30 for warmer weather). I have a basic stock truck. My wife drives a 2005 Buick Rendezvous and her mileage stays pretty much constant no matter what the season. Most likely a bad comparison though since her Buick is loaded with all the bells and whistles and my truck is plain jane. Anyway, I haven't written down my recent mileage but I did check it several times and while I used to average 21-22 mpg I believe I am now getting somewhere around 18-19 mpg. That might not sound that bad but considering the price of gas it's not that great either. Maybe I'm over reacting but it just seems odd that with all the high tech computerized systems used in todays vehicles that gas mileage would change that drastically when the outside temps drop a little.

 

My truck avg 20 in summer, 17 in winter. Wife's car avg 30 in summer, 26 winter. Just the way it goes.

 

I've dropped 7% in fuel economy since october, I was averaging right around 21.5mpg, now I'm down to 20mpg. Same commute, same driving style, same 87 octane fuel, the only real variable is ambient temp. Apparently it makes a huge difference!

 

I'd be surprised if there was anywhere in the country that sells 100% gas anymore. At least here in New England all you can get is a min. 10% ethanol mix.

 

You could try premium, it won't hurt anything. For cars that can't use it, it's just a waste of money. Premium is recommended for vehicles with greater than 10:1 compression. The V6 truck is right at 10:1. Also, I believe the owners manual is the same one as the 4-cylinder trucks. Try a couple of tankfuls and see if your mileage increases. I get about a 1mpg increase with Premium (measured over many tanks). If it doesn't help, you can always go back to regular.

 

I think California averages about 5.7%.

 

Generally when it is colder:
the lights are on more because there is less daylight
heater blower is on more
if the AC is tied to your defrost, it runs more often
the air pressure in your tires is less
tires, belts, etc are harder and more roll/movement resistant
the ethanol and warm up issues as stated above
the volume of fuel actually shrinks as it gets colder, if you buy warmer daytime gas

I used to squeeze 43mpg winter/52mpg summer out of a hybrid Civic, haven't ran any numbers on the the Tacoma yet.

 

Gas addatives will vary with location and can cause some of it.

If your roads aren't icing up, check your tire pressure (which can reduce from colder air, which will in turn hurt your mpg a bit). If you're driving on ice the lower air might help a litte bit with grip, otherwise maybe add a bit of air (remember that the pressure will come back up in the spring, so check for over-inflation when it warms up).

You're pulling in denser air, which will make the computer push more gas since it's controlling AFR rather than just pumping constantly based on engine revs. This will make a little more power but also consumes more gas and can drop your mpg.

Not sure if the heater and lights would amount to a significant draw on these engines (heat comes off the engine coolant and the added alternator draw for lights/fans is a tiny fraction of engine output), theoretically there's a bit but it'll hit you harder in a prius than in a taco since the draw is a bigger chunk of gas engine hp on the hybrids (I've never noticed a difference in mpg for constant A/C use vs no A/C use on any engine over 170 hp).

If you've swapped for snow tires, they may have more rotational inertia than summer tires (probably not if you're running A/T tires, but it's possible), and will take more work to spin up, especially if you're getting show packed into the tread while driving.

About the only things you can control would be tire pressure and easing off the gas a little (I suppose you could take out some tubing on the intake so you're using hot air out of the engine bay, but that'll cost you some horses, and generally I wouldn't reccomend even considering it)

 

Didn't expect this many responses this fast. Lots of good info. I guess I never used to notice the change in fuel economy since I always drove older cars/trucks that never got that great of gas milage anyway. This is my first new truck. I try and keep my tires (stock by the way; no need for ice/snow tires around here) inflated to the reccomended pressure per the door sticker. I have an air compressor in my garage and this helps a lot. I can tend to get a bit lead footed now and then but I'm trying my best to control that since I know it can wreck havoc with gas milage. Guess I'll just have to get used to the fact that my fuel economy will drop some in the winter. I never really noticed fuel economy suffering in the winter before when I drove the older stuff and I used to check it all the time. Maybe I'm just starting to notice it more now what with gas prices being what they are. Then to I never really expected to get any outrageous gas milage with a fairly big truck. The Tacoma might not be up there size wise with say the Tundra or some of the other big iron out there but it ain't little either. Still, all in all I really like my Tacoma. I think it's gonna' be a great truck for me.

 

Depending on what you mean by "older" that could be part of it. Anything with a carb (and probably most of the early FI engines) wouldn't be set up to add more gas along with denser air since the intake systems didn't have mass air flow sensors to know the difference. Also, lots of stuff has been getting heavier over the years (my 2010 prerunner weighs 800 lb more than my old '97 xtra-cab v6 and the engine's got over 20% higher displacement and makes 40+ more horses, although all that only looks to be costing me 3 mpg with the improved computer systems and computer fuel injection/ignition and variable valve timing).

Don't feel bad about a heavy foot, I've been having my back end get a little loose on right turns, even on dry pavement from power oversteer and not much weight in the back. Probably doesn't help that I'm alternating days between the taco and a lowered RX8 which had a powerband that starts at 5k rpm ("redline" at around 9-10k, but unless you overheat it's tough to over-rev a wankel since there's no valves to limit things) and can make most corners at 40+ mph without slipping a bit, but I love the thing too much to let it go and it's actually a safer car in the rain (not much for off-roading though with < 3" ground clearance and a nose that scrapes on sport ramps).

 

OK, you got me there. Guess I'm showing my age. When I said "older" vehicles my last one was a 98' Ford Ranger. It was a good little truck with the biggest V6 Ford offered, auto trans, extended cab, 2wd and, of course FI with a wicked flamer paint job that the guy who owned it before me had put on. It drew attention and lot's of comments. When I bought it I got ragged a lot by my friends an co-workers and it was known as my "mid-life crisis truck". I guess maybe the fact that I was 61 when I bought it might have had a little to do with it. Anyway, I haven't had any vehicle with a carburetor since I can't remember when. The closest thing to a carb was a Chevy Cavalier (can't recall the year) that had throttle body FI. This "car" was one colossal piece of junk. The Ranger was my last truck before my Tacoma and the Ranger got descent gas mileage. I never saw my fuel economy change with the seasonal changes and this I'm sure has a lot to do with why I didn't expect the Tacoma fuel economy to change like it has. I guess comparing a Ford Ranger and a Toyota Tacoma is like comparing apples and oranges but you can only compare what you have driven before to what you drive now. I know there is a big difference between a 98' Ford Ranger and a 08' Toyota Tacoma and I have several co-workers who have Tacoma's identical to mine and we all get different fuel economy although we aren't all that far apart. I've learned a long time ago though not to rely on what someone else says because of all the variables involved with different driving styles, type fuel used, etc.

 

Your truck burns more gas, trying to get to optimum temps during the winter/cooler months than it would during the warmer months. Not sure how much more gas is used but it could be significant if its colder and the truck has been sitting for awhile.

 

The cooler denser in the winter air requires more fuel to keep the same oxygen/fuel ratio. The ECU detects this throught the inlet air temp sensor and richens the mixture accordingly. A 6-9% drop in mileage is not uncommon in the colder months. But on the up side, in cold weather, the motor is making that much more power.

 

I had an '85 Cavalier (or Cadavalier, as I now refer to it) before I got my first Taco. The Toyota dealer gave me $200 on the trade-in and I almost felt guilty taking that at the time (less so as I've learned more about the reputation/business practices of that particular dealer). Got the car for free from my grandparents when I was in college and ultimately still ended up feeling a little cheated with the time it took to maintain (could've bought a decent used honda or toyota for the $$$ that chevy cost in repairs every month once it passed 60k miles).

Welcome to Tacoma ownership, I loved my first '97 (even if it was just a street-rigged 2-by) and wouldn't have sold it if I'd been able to manage 2 vehicles when a RX-8 test drive hooked me. Haven't really broken in my 2010 so far, but I'm liking it so far; could do with a stereo upgrade, but not getting the JBL system was my choice, and audio is now on my to-do list along with mounting a hi-lift and adding some tie-downs low in the front of the bed and probably someday a winch.

 

I usually get around 300 miles per tank up until about 1 month ago. All of a sudden it dropped to 230 miles per tank. I changed my air filter then it went back up to around 270 miles. I wondering on what caused the significant drop. Then I realized that since it is getting a lot colder now, I start my car up for about 10 minutes before I drove anywhere. I like the truck to warm all the way up (needle at the middle on the temp. gauge). That's probably what's killing my gas. Maybe 5 minutes should be good for then the full 10 once it gets below freezing outside.