Hyundai Repair: Fuel consumption, poor fuel economy, automatic hyundai

Question
Hi,
I have an automatic Hyundai Elantra 2000. Before getting to this cold weather in January, and in tempratures around 5-10C, its fuel consumption was 7 to 8 Liter/100KM in highway and around 10-11 Liters/100KM in city. Now that we have got into -15C to -20C, it consumes some 18-20 Liters/100KM. I normally turn on the car some 3-5 minutes
before starting to drive, just to make it warm (looking for temrature gauge to come up a bit). The heater is also mostly on to the most speed. Do you think there is any problem with the car fuel system, or maybe its my way of operation that makes it drink gas!?

Answer
It's difficult to say what the cause may be without knowing your driving habits.  If you're making short trips, then the 3-5 minutes warmup each time you start the car can be a significant portion of the fuel consumption.  I'd also expect the cold weather to play a role, but not to the point that you used twice as much fuel.  

The numbers you report for normal fuel economy do seem about right.  They translate to about 22 MPG city and 30 MPG highway.

If your check engine lamp has illuminated or the vehicle doesn't seem to be running normally, that's a good indicator you have a problem with the vehicle that may be contributing to poor fuel economy.

You'll need to weigh your options to see whether you should simply wait for warmer weather in an effort to determine whether the fuel economy will improve, or you should take the car to the shop to have it checked.