Gas Mileage Mystery

[Wayne County Hose]

Nat hit it. It's the oxygenated fuel. It's used in certain states or counties here in the northeast during the colder months. Why, I forget, but I know it's something to do with pollution. Oxygenated fuel is supposed to burn cleaner, but it takes more fuel to go the same distance.

 

[mjfox6]

things i have read, say you get better gas mileage with the lowest octane, unless your vehicle requires the higher octane: i have checked this on a couple 2,000 mile trips: went from Arkansas to Pa and used the cheapest fuel i could find, the used a grade or two better coming back and got the same fuel mileage, with no difference in performance i could detect: i have done this little test twice over the years and i came out the same both times: this was driving a toyota extended cab tacoma, 4cyl, 5speed manual transmission: 2 different trucks, one was a 93 model, i don't remember the year of the other one.
heehaw

It's uphill from AR to PA, shouldn't you have gotten better mileage coming home just because of that? A round trip with each octane would be a better representation of mpg.

 

[dmccarty]

My diesel gets about 1-2 MPG less, 5-10%, during cold spells than when its warm/hot. This is hand calculated not via the overhead computer.

Someone posted a link to getting better MPG a while back. According to that doc, I think Mac Truck put it out, winter MPG declines are due to denser air(colder) which effects both wind resistence as well as your tire pressure if you don't check. And it takes much longer to get the engine up to operating temps. To prevent gelling, fuel additives can also lower the energy content of the diesel. Not sure how big of deal this is anymore though. I am assumed they meant mixing Kero with Diesel.

Pretty sure oxygenated fuel is no longer used. The mix went to Ethanol instead. MTBE was very water soluable and cause problems with the water table around stations that leaked fuel. It was a known problem before MTBE was regulated into usage.

Later,
Dan

 

[RavensRoost]

Might be time for a new oxygen sensor(s).

RavensRoost

 

[Egon]

Gasoline, just like Diesel has a different blend for winter conditions.

 

[RockyMnt1]

2 things affect my winter MPG:

1) snow tires
2) Oxygenated fuels

I use the lowest octane fuel (85 here in Co). Now, my MPG is around 39-40 MPG. My MPG picks back up to 42 MPG in April (1993 Honda del Sol, 5 speed).

 

[DUMBDOG]

Colder temperature means longer time to warm up and colder intake temperatures equals poorer mileage. Happens every fall for the last umpteen years.

 

[Bird]

I keep more detailed records than most folks and have a spreadsheet with every nickel spent for gasoline the last 5 years that we've owned our 2001 Windstar. As of June of this year, the overall average for 4.5 years was 20.003 mpg. And that was when the overall average began to come down. For the period of June, 2007, through January, 2008, it's averaged 17.87 mpg. Our vehicles don't spend time idling to "warm up" but we do get caught in traffic, so I know that part of that mileage decline is the result of many shorter trips and heavier traffic, but I think the difference in the gasoline accounts for some of it, too.

 

[pennwalk]

Jeezze Bird,

It's a good thing I'm not into conspiracies or I would begin to wonder if someone had found a way to sell us more gas. Naw they wouldn't do that... would they. Heck, the Government wouldn't let them ... would they...

Chris

 

[Wesdor]

Once again, Thanks Bird,

I also keep detailed records (in my case they go back more than 20 years) on our vehicles. My 2000 Dodge mini-van dropped from 21 to 18 this winter and I'm looking forward to better weather and hopefully better mileage.

Thanks for confirming that the drop isn't unusual.