Have a new 2012 Sonata SE 4 cyl. Getting 18 mpg city and 20.5 road. Anybody else have same problem? Took back and they state they do not know what is wrong. They had car 4 days and released back to me with same low mpg (plus some mechanic left a baby bottle in trunk). Also one AM radio station has 'squalling' and cannot be used. Satilite stations do not make sense - do not progress like AM/FM stations. Wander into their own selections. This is my 2nd Sonata and nothing like my first (2009) which was getting 24+ in town and up to 39 on the road. Very concerned.
You don't say if your engine is the tubo or not ut I'm uessing you have the 2.4.
I have one and I get 27-29 mpg suburban anf 33-34 mpg on interstate travel so I agree your Sonata isn't right. Here's what I recommend you do before visiting your dealer again.
1. buy your own OBD II code reader, about 50-60 bucks and check yourcar's condition.
2. check to see that your intake air filter is not clogged. Same for intake air piping.
3. check your exhaust sytem for dents that reduce exhaust flow.
4. watch your mpg bar as you drive - don't do it continuously, keep your eyes on driving - to see that you're at least doing the more economical mode of driving. If that bar is low all the time there's something wrong. Either you drive with a heavy foot, use the wrong gears, make very short trips, say 5 miles or less. Verify that your Sonata s getting into6th gear as quickly as possible by flicking the upshift when it should be in 6th and verify that it dioes say 6.
5. Make sure your tires have 35 psig pressure.
6. insure your alignment is good; poor alignment really eats mpg.
check your mpg by dividing miles driving since filling the tank
(and resetting the trip odometer) by gallons to refill. That gage is not infallible but usually ptretty good..
If you still get poor mpg your dealer should reset your ECU at least. Make sure you aren't using a 40 or 50 weight oil.
CHECK YOUR BRAKES, you may have a sticking piston that drags the pad(s) on the rotor; check your emergency brake as well. Make sure its fully releasing.
good luck
