Bought a 2012 Sonata in January. Glendale Hyundai. 4 cylinder. Current miles per gallon is 18 in city and 21 on the road. Glendale Hyundai had car for 4 days and cannot find anything wrong. Say they are waiting for a Hyundai specialist to look at it. Gave up calling as they are slow in returning phone calls. In meantime I am losing a lot of sleep over low mileage. My 2009 Hyundai Sonata was getting 24+ in the city, and 35 or better on the road. Unfortunately it was totaled and thought I'd just replace it with another Hyundai. They claim they have no idea what is wrong and do not know 'when' the special Hyundai technician will be available. Find it strange they don't know when one of their special technicians will be available -- don't they work for Hyundai? Also my radio is not functioning properly. So far this car has been a big nightmare/disappointment. It's my second Sonata, and the 6th Hyundai in our family. Not happy.

 

No problems with mine except had alignment at 3000 miles.
Fuel consumption averages 30 or over combined city/highway.
Gil

 

are you using ECO? we did for the first couple of weeks, and got dismal mpg- turned it off and it's fine

 

rosiethered I also think mine gives better mpg with ECO OFF!