Recently, the weather here in midwest has been freezing cold as average of -5 to 5 degree outside and my IS250 gets horrible gas mileage.
I used to get about 350 miles with full tank, but it dropped down to 200 miles now. Is this because of the low temp?
Also, I remember seeing a thread saying that warming up our ISX50 before on the go is not good for the engine. Would that theory apply even at this cold weather?
Thanks in advance

 

it should not have to much to do with it.The colder it is, more fuel is added at start up,but their are various factors to this also.When cruzing I would think better gas milage(cool dense air)maybe idealing alot would cause this.Lexus says no need for warm up but with it -5 degrees i`d warm my car!!!I just do not want my hands to freeze to the steering wheel.Plus its never a bad idea when below freezing to allow a little warm up.

 

What type of driving do you do, all hwy, all city, a little of both. Reason I ask is our cars will hold a lower gear until the car is warmed up. With the colder temps your car might be holding a lower gear longer to warm up. I don't see this making up the whole 150 mile differance but it could be part of it.

 

I have been experiencing low mpg lately as well. Its due to the cold weather, plus i do mostly city driving which makes a considerable difference in the winter.

 

I have to agree, even here in Houston, TX I've noticed that my gas mileage has dropped slightly since its been cold.

 

I heard that gas companies have a winter mix for their gas. This is done for emmissions and does hurt your fuel economy.

Now, dont quote me on that, as it is just something I have seen reading the Message boards

 

actually in cold weather you should get better gas milage.

 

this is another way of thinking.. since the car performs better in cold weather, you are likely to push the car harder thus giving poor gas mileage

 

Cold air + cold fuel reduces atomization. When I lived out in the country in Virginia, my fuel economy dropped exactly 10% when cruising on the interstate during the winter.

 

I normally drive city driving and very short distance. Therefore, often times, I get to the destination before the temp gauge reaches the middle.

 

Yeah, I read once at the chevron website, fuels are a little more volatile in the winter, the winter mix vs. summer mix. With the winter mix you just don't seem to get the same mileage.
Your car may, just like some of us oldies, gets a little bit stiffer in the cold. My Jeep always drops to the 15-16 mpg when the temps go low. That 80 weight, in the differential lube gets pretty thick in the cold mornings. I don't know what weight is in the IS350's differential.
I like to let the oil get worked up in the motor good before driving off. So I let it idle a little longer in the winter. One thing about it, this cold will find a weak spot,(if there is one) with your automobile. cold is unforgiving.

 

In decades of driving many different makes and models of cars, I've never yet seen a single one doesn't get poorer fuel economy in cold weather.

 

Ethanol added to your gas will also reduce your mileage. I've seen a 2-4 MPG drop with the 10% stuff that works its way into my tank every now and then.

 

Engines run off of heat. When it is colder, it takes more heat just to get to operating temperature. You're bound to use more fuel. There are also a bazillion little details about the physics of the situation that all mean efficiency suffers, and the oil companies produce a different fuel blend in the winter with a lower specific heat. So, you mileage will suffer. I can't even break 26 mpg on my drive to the Bay anymore. I'm sure it will go back up to 28 - 29 by springtime though.

 

Looks like the last tank of gas I just got is the 'summer' blend. Through last summer, my overall average was just under 27 MPG. During this winter, it dropped down to about 23-24 MPG. I'm averaging 26.4 again this tank.