Winter Gas Mileage

jaslo · February 19, 2008

I am wondering how much has your gas mileage went down this winter? Mine has went down 3 to 4 mpg and is about 1.5 to 2 mpg worse than this time last year. I live in MO where they switched all the gas to have at least 10% ethanol, but I have never gotten this bad of gas mileage. Do you all think that the combination of winter gas plus the ethanol in the gas is making me get this bad of gas mileage. I am getting about 15 mpg on all highway mileage.

Volucris · February 19, 2008

Yeah, my mileage dropped about 2 mpg. Ethanol is what does it here.

vranasaurus · February 19, 2008

I am wondering how much has your gas mileage went down this winter? Mine has went down 3 to 4 mpg and is about 1.5 to 2 mpg worse than this time last year. I live in MO where they switched all the gas to have at least 10% ethanol, but I have never gotten this bad of gas mileage. Do you all think that the combination of winter gas plus the ethanol in the gas is making me get this bad of gas mileage. I am getting about 15 mpg on all highway mileage.

Cold air is denser leading the ECM to put more fuel in to keep it at the optimum A/F ratio. The colder the air the denser it is.

A gallon of E10 contans 97% of the energy of a gallon of gasoline. So you'll notice a slight drop when using E10 but not much. Even if it was 3% percent that is only about .5 MPG less.

jhoff8487 · February 19, 2008

My mileage has taken a sharp drop. I attribute it to winter gas blends and I changed my driving patterns at the turn of the year. I used to drive 30 minutes or so to work, now I start her up, warm it for a minute or two, drive 3 or 4 minutes, and shut it back off. My mileage sucks but at least I know why.

Westlotorn · February 20, 2008

Just used my Tahoe, 2002 5.3L 4x4 with 4.10 gears on a 360 mile trip. Drove 70 to 80 as trafic allowed with a little in town driving in the middle. Got 18 straight up. I was pleased. Did not use cruise control it seems to cost me at least 1 mpg each time I use it. Did not run the AC on this trip. What do guys get that have the 3.42 or 3.73 options? I always wonder if I am missing on mileage because of the 4.10s. My Denali 2001 with 3.42 gears and the 320 HP 6.0L never gave me 18 on a trip no matter how much I pampered it. The same trip in it would nave netted 16.5 usually. It was fast though!!

LAGA · February 20, 2008

Mine has gone down 2 mpg. In Chicago, it is 10% ethanol all the time and then they hit us with winter gas for about 5 months. Mpg will go back up usually in mid March

2000DV4.8 · February 20, 2008

It's about 3 mpg worse than it was this summer. Probably because I'm letting the truck warm up more, I have mud tires on now, and about half of my drive to school is stop and go. I hope it goes back up when it gets warmer... 13 mpg is just depressing to see. I did get 16.2 on a 300 mile drive this weekend though. That was reassuring.

Zembonez · February 20, 2008

Mileage here is actually a bit worse in the Summer. Or course it also doesn't get anywhere near cold here. (not by northern standards) I don't know if they change the formulation here for Winter or not. I generally get about 1 mpg worse in the Summer using the AC all the time.

EDIT: I'm told that here the Winter formulation is no different than the Summer version. That must be why my Sumer mileage is actually worse.

J45p3r · February 20, 2008

I drop 2-3 MPG in the winter.

GM Dude · February 20, 2008

I'm not real sure about my summer mileage since I just got my 08 in December. Nearly all my trips are short and I net around 13.5 to 14.0 and it really doesn't get cold so I don't know if they use a winter mix. My truck is set up with the flex fuel option but nobody carries it around here and I plan on a few hundred mile highway trip soon so I will report back on my highway mileage. I'm running the same setup as my 05 GMC, 20" tires and 3.73, and it is on par with it although I would have thought I'd get a little better with the V8/V4 mode 'cause it seems I'm in V4 a bunch.

jaslo · February 20, 2008

I just filled up the truck tonight. Got 15.5 mpg. That is mostly highway mileage. 20 miles to work, 20 miles back. Usually I get 18 to 19 in the summer. I hope my mileage comes back when they quit using the winter gas because this is depressing. Usually in the winter I would at least get 17 mpg, now I can't even get that. Wife filled up her truck tonight. She got 14.5 mpg. She does mainly city driving, but her mileage is down about a 1.5 mpg from last year this time too.

strafingmoose · February 20, 2008

I got a whooping 13-14 to show for as of now. Just bought the beast so I don't know what it'll do this summer.

Hope to get something like 17-18 which seems average for a 4.8 on 2x4.

jwhjr · February 20, 2008

2-3 mpg drop for me

silverado02excb · February 21, 2008

I just filled up the truck tonight. Got 15.5 mpg. That is mostly highway mileage. 20 miles to work, 20 miles back. Usually I get 18 to 19 in the summer. I hope my mileage comes back when they quit using the winter gas because this is depressing. Usually in the winter I would at least get 17 mpg, now I can't even get that. Wife filled up her truck tonight. She got 14.5 mpg. She does mainly city driving, but her mileage is down about a 1.5 mpg from last year this time too.

I am getting almost identical. 30 miles each way and getting 18-19 in the summer, now getting 15-16. I agree with others that running richer with colder temps is main contributor as well as starting in the am to warm up. Come on spring!

SnowGoAK · February 21, 2008

A couple weeks ago I drove 160 highway miles at -26F below zero and averaged 11.5 mpg in two wheel drive. At 70F in the summer on the same trip I averaged 22 mpg.