My '01 GS430 has been averaging around 18.8 mpg in city driving since I've had it. However, I'm about 1/3 of the way through this tank, and I'm at 17.2. My driving style hasn't changed, and I'm still driving on the same roads. The only difference is that this tankful started when the temp dropped down to low 20's at night and high 30's in the day.

I don't think that the air temp would have that big of an impact on the gas mileage, or does it? The car has recent Iridium plugs, and the tire pressure checked out to what the factory specs call for. Even stranger, I always fill up at the same gas station (hey, it's close to the house), so I don't think I got a bad tankful of gas, though it is possible.

 

Winter mix blends of gasoline often results in a slight drop in gas mileage depending on the brand of gas..

 

Yes. That's normal. Cold weather and winter blended gasoline does affect gas mileage.

 

1 mile isnt a big drop probablu just the waether and gas like they said

 

The colder it is the longer the car takes to warm, and when warming the car especially on start up, it runs rich, thus spending more fuel

 

Well, that makes sense then.

What's the reason behind summer and winter blend of gasoline?

 

http://www.slate.com/id/2098672/

 

Interesting read.....thanks GSteg!

 

what a waste of a thread....

 

I completely and utterly disagree. I was actually thinking the same thing recently. At first I figured that maybe the cold did affect it. But then I thought that I drove it from a cold engine the same was as well. I didn't think about the different mix for gas though, which is probably the culprit with my poor gas mileage . Last time I filled up, I got an abysmal 19.5mpg (which is compared to my average 21-22mpg).

 

my 400's MPG has dropped from 17/18 to around 13. i am wondering if it might be the gas im using. next fill up i will try a different brand.

 

yea ive been getting 17mpg average n i drive 80% hwy... i wonder why... :3

VROOOOOOOOOOooooooooooooooooooom

 

report back if you're still seeing a change after 3tanks.

 

I'm right there with you...i'm in NY btw. It's cool bc my new job requires me to take the train, so no crazy gas expense. But now I get blasted with the train expense. Lol

 

colder air, increase in density of air, needs more gas to compensate for the increase in density?