I thought about your suggestion Kurtz, but I'm not going to take that trip. Firstly, my car is no longer under warranty, if I took the trip, by the time I come back, it'll be at 53,000 miles. I don't have the time to travel 300 miles right now, still rushing to get my college applications in. My parents will be wondering why am I traveling 600 miles total for no apparent place to go to. About a 10-12 days ago, I traveled 100 miles on the highway and half of the tank was gone so I doubt it can do 300 miles on a full tank. But I'm not complaining about my gas mileage, when I got it two months ago, it was 12.8 MPG, a month ago it was 14.6, now it's up to 16.6 MPG. I still have to change out the spark plugs soon and clean the air induction system once it gets warmer outside.

 

I'm always in automatic. This is my first car and I'm only 18. I'm too dumb to drive it in the manual mode, even though it seems very self-explanatory. It can't be my driving, I accelerate from stops up to 2500 RPM max and drive around 35-40 MPH. My driving is 75% city/25% highway where I travel anywhere from 40-80 MPH, depending on the traffic, but I'm usually only on the highway for 6 miles of the total 24-27 miles I drive a day to and from school.

I have no clue why it only gets 16.6 MPG when I don't drive aggressively, it's up to date on maintenance, and the guy who checked out the problem at the dealer said nothing's wrong and the car is in very good shape. And I live in Chicago so there's barely hills.

 

no offense man but sounds like your not experienced in snow driving. I drove last winter in snow and went snowboarding and had no problems on stock tires. This year I'm on 20's on continental DWS's so hopefully they suffice.

 

How are you measuring your how much MPG you are getting? Is it strictly based off what the display is showing "avg tank" or "avg mileage" ? If so, it could just be an error in that and not your actual mileage.

A way I measure my mpg is get my tank completely empty, then fill it all the way up and reset the Trip A odometer to 0. Then drive the whole tank, and at the end you can divide the number of miles you've driven by how many gallons you put in the tank.

From a full tank to an empty tank (prolly not exactly empty, just on the bottom line at E) I get anywhere from 360-400 total miles.

 

It's okay, I'm actually not experienced at all. This is my first car and the first time I drove in actual snow. The last time I was close to driving in snow, slush, was when I drove my brother's Civic to the store to practice for my driver's license. So yeah, pretty much no experience at all in snow.

Any tips you can share? So far I'm just going to try out how this car handles in snow, add some weight into the trunk, and drive in problem areas like my garage/ally and parking spaces in 1st gear only.

 

I simply use my odometer, record the current mileage before a fill-up, fill it up full, and drive around. Then, when the next time I fill up, record the new mileage, subtract the old from the new, and fill up full again. Take the difference in mileage and divide by the gallons just filled up with. Sorry if I made it sound confusing, it's actually simple. My "Tank AVG" says 15.4 MPG and "MPG AVG" says 20.2 MPG. My math says 16.6 MPG most recent fill-up.

 

Looks like there is the problem. From that I am getting you are taking the miles you've driven on one tank of gas and dividing it by the number of gallons you filled up for your next tank of gas, so the numbers are not matching up.

Try doing what I said earlier, using the trip A odometer, a lot easier and don't have to write anything down.

Also, the tank avg/mpg avg reset each time you fill up anyways (I think), and only get close to accurate after you've started driving and emptying out your tank. Also the "range" it shows after you filled up is also a guesstimate based off how the car has previously been driven since the IS does have a memory system. Since it is a used car, it can still be judging based on the previous owner who may have ragged the car a lot.

 

somethings that affect gas mileage are bad alignments, dirty air filters, low tire pressure, bad tires, etc

get your alignment checked up, make sure your air filter isnt too dirty, and fill the tires with the recommended psi levels and see if there is a difference

 

Any third party modifications which could be onboard the car as which could be contributing to this?

 

No I live in WA we got about 3feet of snow untouched but even plowed I couldn't move my car if didn't make out of the drive way lol I had to wait for help to move it back in so I just I just drive duramax

 

my car handled the powder/slush/packed snow quite well. RWD.


the winter blend gas affects your fuel economy too. my fuel economy has gotten
~1L/100km worse since about a month ago from the winter blend gas.

 

R u sure u r looking at tank avg readings? I think you are looking at lifetme avg which is misleading as it accounts for prior driver usage

 

Engine and transmission are warrantied for 6 years/70,000 miles FYI.

Doing all highway I can get like 400-450 miles out of a tank, so if you burned half a tank in 100 miles, again, there's something wrong with the car.

 

best tips I can offer, is wait until it snows, find a parking lot and have fun. That's the best way to learn how to control a RWD car. You have to be easy on the gas and learn to steer out of situations. If you lose control on a turn oversteering, dont touch the brakes!!! You have to just let off the gas and steer it out. Driving a RWD car in the snow is all about steering and being easy on the gas pedal. If you revved up to 7k, then you were being way too aggressive with the throttle. I didn't use snow mode all winter but you can try that as well.

 

Unfortunately, the is350 doesn't have a limited slip rear differential, so even with snow tires, going up an incline is a pita. If one tire looses traction and spins, the other one just sits there and looks pretty. Disappointed at the japanese