My city mileage went from...
 

My average city mileage went from 25-26 to 21 in one tank. Highway mileage I do not know what it is doing? I can tell it is much worse and I am not happy about it.
There are other factors not just winter gas blend. Lately the wind has been very bad with the cold fronts coming in. During the Summer there is usually a mild steady breese coming from the south. Some of these cold fronts have the wind howling and even when it is coming from the south it is still stronger during the Winter. Oil is much thinner when it is hot. We do not let the car warm up in the Summer.
There may be other factors I do not know about but we know mileage has took a dump and quickly.

Granted I do'nt have Ohio winters, but my mileage stays the same. Our lowest temp so far this winter has only been 17* though.

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They add ethanol to the mix year round.

[QUOTE=solman98;341022]Granted I do'nt have Ohio winters, but my mileage stays the same. Our lowest temp so far this winter has only been 17* though.
QUOTE]

yeah we had -2 a week or so back. my blue baby did not like that at all. she did not want to go at all. but i did some hwy over the weekend and focussed a little more on my hypermiling and i got the mpg up to 25. i still want it back up to 30.

X5... but necessary when the mercury hits -30F (without accounting for the wind chill) and you need her to start without having the block heater plugged in.

did some researchin and there is a difference between winter and summer blends of fuel. they both have ethanol but winter has on avg 1-3% more. also winter has some more random crap. ill try to find a link when i get home from work.

There are a whole bunch of factors that come into play in cold weather.

Winter blend fuels do not have the BTU (energy) content of summer blends.

In cold weather, fuel mixture is much more rich during warmup. That is a much bigger factor in "short" trip driving.

Tire pressures decrease when colder. Check 'em! (And that goes for you Nitrogen fans, too, since the same applies!).

The tire rubber gets "stiffer" when cold. Rolling resistance goes up. Same applies to lubricants when cold.

Add 'em all up and you will see a drop!

For my car I know tire pressure is good
 

I just checked and aired up my tires. I know that is not my problem. Oil and all other fliuds are thicker when cold. Do not know just how much of a difference that makes.
Maybe the choke circuit is pretty rich? Car definatly starts up and runs good in cold weather. Plus the weather (and mileage) had been pretty consistant until the last tank.
I think 4 MPG on a tank of gas in the city is a big difference. More than I expected or want.

One thing that makes me curoius is it appears that a crosswind hurts MPG more than a head wind? Any opinions on that? Still there has been a lot of wind lately and no matter what direction unless it is a tailwind hurts you. Just do not know how much.

aired up the tires and rotated, up to 27 now. still not the clost to 30 i was getting in the summer. just have to wait till spring to get that bac

change oil
 

i just changed oil , put in synthetic, mpg is better. while on highway i try to go 66mph it is a "sweet spot" for my 08 2.4 auto panel. i drive 270+ miles 6 days a week. i still go faster sometimes. i am most always concience of my engine speed. i tryed old trick yesterday , it does not always work , but sometimes when taking off from a stop , while getting slowly up to speed i let completely off the gas , sometimes this will make the trans shift to the next gear sooner -decreasing rpms and the amount i spend at the next fill up.i have to fill up daily , you can believe i watch everything about my vehicle. the oil , the speed , and the easing up to speed , and letting off , all work. i have tried not doing any one og these things , and it did make a difference. i just purchased my hhr a month ago , so i do not know what it does in the summer. but i increased my mpg from 24 to 27.

Mine's been steadily going up since summer. Go figure.