weather and gas milage?!?!

[odie301]

i notice a drop in my mileage when it gets cold out as well. I recently put in e3 spark plugs, and a fuel filter..I then recorded an avg of 16.5 mpg which was .5 over what i was getting all summer. Now since the temps have dropped here in minnesota..i have gone back down to anywhere from 15.5-16. this is all with the same style of driving. Maybe they add more ethanol into the mix because of the cold??

i also remove my cooling fan when the weather gets colder as my truck always seems to run "cold".. i know that it uses more fuel to help warm the motor up, which could be the reason for my mileage decrease?...I thought about blocking off part of the radiator with some cardboard to help it warm up in the mornings..but i dont want it to over heat.

 

[gtbigup01]

plugs are good, recently replaced. All scheduled maintanace is way over done... i can check but i seriously doubt that the problem is with the little things (i.e. pluggs, wires, filters, etc) as I am pretty maticulous about upkeep.

It was tuned during the summer months here in Phoenix. not sure how much effect that has coming into winter.

Tire pressure is 30psi cold... just checked.

And to clerify, I get 20+ mpg's because I do about 95% of my driving on the highway

20+ mpg? I cant even get over 13.8 on hwy, ok so i've got a denali but darn that much of difference from the 5.3 to the 6.0. I'm in FL now heading back to ga in a few hrs (6hr drive) so lets see if i can get 14 mpg, oh wait too boring driving 55mph. I guess it'll be 13.8 again

 

[Max]

Maf or filter could be dirty as the high idle from a colder start shouldn't make that much difference. I went from 17mpg down to 14mpg the past week when it snowed but that was due to the constant remote starting and lots of throttle in the snow. You may have filled up at a bad station too I've done that before.

 

[Eagle]

And to clArify, I get 20+ mpg's because I do about 95% of my driving on the highway

I soooooo hate you. I get 12mpg in mostly freeway or freeway speed driving.

 

[tx tahoe z71]

I soooooo hate you. I get 12mpg in mostly freeway or freeway speed driving.

Get that sh*t tuned! I went from 16 on the highway to over 20 with a tune. City went from 12ish to over 14.

 

[tybardy]

Maf or filter could be dirty as the high idle from a colder start shouldn't make that much difference. I went from 17mpg down to 14mpg the past week when it snowed but that was due to the constant remote starting and lots of throttle in the snow. You may have filled up at a bad station too I've done that before.

for sure not the gas. I thought that might be the case so I waited a few weeks before posting this question. I have filled up severaal times now. I also dont think its my MAF unless it is just going bad, I clean that thing every other oil change or so. I suppose I could clean the air filter... it shouldnt be that dirty though, not many miles on it... I dont know how to clean a dry media filter though. It didnt come with any cleaning instructions or cleaning solution.

 

[Eagle]

It is October. That means winter gas is now in the tanks at your local station, and may now have up to 10% Ethanol in it. the fact that it has been several tanks since October and all give the same result, as well as the timing of the change (no real weather changes)
old article, but states that AZ DOES switch blends and does use ethanol.

http://www.azag.gov/consumer/gasoline/gas.html

"While increased crude prices are partly responsible for higher Arizona prices, other factors, including the spring transition from the winter to summer fuel blend, extensive refinery maintenance and the switch from MTBE to higher-priced ethanol as the oxygenate in reformulated or 'Cleaner Burning Gasoline,' also impact the price Arizonans pay at the pump."



The Phoenix metropolitan area, including Maricopa County and parts of Pinal and Yavapai Counties, is required to use special gasoline blends during the winter and summer to meet federal air quality standards. Tucson also uses a special blend during the winter months. The rest of Arizona, outside the metropolitan Tucson and Phoenix areas, uses conventional gasoline year round.

Arizona’s special blends are credited with improving air quality in the Phoenix and Tucson metropolitan areas. Industry analysts and refiners, however, claim these unique blends are expensive to produce, in part because expensive blend stocks and sophisticated equipment are necessary to produce the specialized blends and the number of refineries that produce them is limited.




Last time I was there, gilbert was near phoenix.

---------- Post added at 10:17 AM ---------- Previous post was at 10:09 AM ----------

I always thought when the vehicle is tuned during warmer climates and the temps drop, that it increases timing and power but does use more fuel as it runs rich. maybe try cleaning the o2's or pull a few plugs and see what they look like.

it doesn't. that was sometimes the case with CARBS, but not efi. EFI self adjusts for either barometic pressure or air temp.

you have MORE than enough air to completely combust all the fuel, all the time, except maybe at WOT w/ forced induction when excess fuel is sometimes used for chamber cooling.