I bought a 2012 Elantra about 6 months ago. One of the primary reasons I purchased the vehicle was based on an estimated 40 MPG highway and 28 city. Unfortunately I am seeing an average of no more than 22-26MPG combination highway and city. The majority of my driving in highway and I am using the ECO mode all the time. Hyundai dealer says the car is functioning normally. I filed a case with Hyundai corporate and they have asked me to take the car to another dealer to perform a mileage test. Any idea what might be going on here? As an FYI, I average about 60 MPH on the highway.
How are you figuring the fuel mileage?
Assuming the mileage is actually down that much, has the tire pressure been checked? One low tire can kill fuel mileage.
The best way to know if a mileage problem really exists is to fill the tank, take an extended highway drive only, and then refill it in an identical manner as originally done followed by dividing gallons into miles.
If an engine was really running this poorly the CEL should be illuminated and various codes should be present.
I feel your pain. I have a 2011 Elantra, 29 City and 40 Highway. I drive to Dallas on occasion, about 250-300 miles one way. I got 39MPG on one trip, but for the most part I get 37-38 max. That is ALL highway driving, nothing else. I drive 72-73MPH on cruise control and on ECO. I can live with that, but the only way I would get 40MPG is if I went 65MPH on cruise. I use the Gas Mileage indicator on the car itself, but I still do it the old way (miles divided by gallons at refill), and I get worse numbers there. City driving? That’s ridiculous. If I do ALL city driving, no highway driving (which is rare) I’m lucky I get 24MPG. Mix is hard to compare, but when I do a mix of driving, it’s around 27MPG. Regardless, the Elantra will not get 40MPG unless you do cruise at 65MPH or less. And that is not normal driving on an interstate. City driving? I couldn’t get 29MPG if I was going downhill in neutral with the wind behind me. Someone Hyundai has worked the numbers on the EPA calculation. I think other cars get much closer numbers to the EPA numbers.
Have fun suing Hyundai. Those 40 mpg values are not Hyundai’s, they are official government EPA figures.
And, as golfdawg points out, the values are likely quite correct for driving at a steady 55 mph on the highway. Do this and you may even exceed the estimated 40 mpg.
Of course no one plods along at 55 mph on the interstate. That’s the fault of neither the EPA or the manufacturer.
I think that most car makers boost their mpg for advertising purposes, don’t you? Personally I usually get HIGHER mpg than EPA of car maker estimates, but that’s me. Do you do the normal stuff for better mpg? Check tire pressure . . . watch jack-rabbit starts . . . empty the trunk of extra weight . . . and so forth? Sometimes cruise control can get WORSE mpg, try a trip using your right foot and being more attentive. Just my two cents. Good luck! Rocketman
To replicate those numbers you’d have to do EVERYTHING they do while driveing as the others have said.
The max mpg tire pressure may very well NOT be what’s shown for Joe Owner to use.
Cruise control gets worse mileage. Conversely, you’d need to gradually relax acceleration and lose speed on the uphills, something cruise doesn’t do, and ever so gently re-accelerate to that never used 55.
From a stop, accelerate like a turtle.
Don’t use ANY accessories that draw power, like a/c.
Reduce overall vehicle weight ;
Use only a patial tank of gas.
Carry NO items , even the spare and jack, in the vehicle or trunk.
calculate mileage only in a tail wind on a flat smooth road. ( rough pavement causes drag )
Plus, I’m sure there’s more hyper-miling techniques.
Dallas to Houston is a pretty flat drive (as is much of Texas). The reason I wonder is that the EPA changed the MPG estimates around 2009, to be more accurate. The old estimates were at 55MPG, no wind, flat track, etc. I would just assume if you are going to estimate highway mileage and be more realistic, you would have to have at least 64 MPH, or 70MPH, which would be what most interstates use as the speed limit.
Ken Green, I have to disagree with you on the AC. That certainly was the case in the old days, but in newer cars, if you drive with the windows down you screw up the aerodynamics of the car, and you can actually lower mileage. This is something I have read in multiple spots.
As far as everything else, yeah, but that’s if you are a hyper miler 
I keep my Elantra on the MPG screen, so I can see how I’'m doing. I will say, as far as cruise control, the comments seem to be correct on uphill. Better to turn off cruise on hilly roads, as the Elantra accelerates heavily uphill. You can see the MPG go down!
Regardless, the highway MPG is close enough for me, but the city mileage is WAY off and is a joke.
Some people are unconsciously always accelerating slightly as long as the road ahead of them is oprn. Then when they catch up to the traffic ahead of them they have to step on the brakes.
Brakes waste fuel every time you use them. They turn the energy you used to accelerate or maintain the cars speed into heat. Drive smoothly and try to flow with traffic. I drive a 2012 4 cylinder Camry and easily get the 35 mpg highway rating using a top speed of 75. Of course I have driven a few million miles.
That reminds me of an old fellow around here ,had a old Datsun or Nissan truck and every time he was asked about the truck he said" uses as much gas as a big pickup" every 4 cyl vehicle I have owned gets around 26 mpg around here(had several) wifes old Accord gets 27,daughters 08 Civic gets around 40 on trip with AC on-Kevin
If there is a mechanical problem behind this I’d look at two areas, the transmission and the brakes. It seems many folks look at the engine first, but often the engine is fine.
Another factor driver’s often ignore is tire pressure. You really need to keep the tires fully inflated to the recommended pressure to achieve anything close to the EPA mpg figures. If you are diligent in checking and maintaining tire pressure you can rule this out. If not, get a good tire pressure gauge and check tire pressures weekly for awhile and see if the mpg improves. Running tire pressures of 25 or less with recommended pressures of 30 to 32 would yield the kind of low mpg you are getting.
As for the transmission, you need to confirm it is working properly. Is the transmission going into torque converter lock up mode? Is the transmission shifting into the highest gear at relatively low speeds on level roads? Is there excessive transmission slip before the torque converter locks up?
The brakes can create extra drag if a caliper is sticking. All 4 wheels need to be checked for easy wheel spin with the car up on a lift. A dragging caliper will kill mpg numbers.
Seems like REAL WORLD the avg is under 30 MPG from people who filled out the survey on Fueleconomy.gov… Click on the show details button for more info.
http://www.fueleconomy.gov/feg/Find.do?action=yourMpgVehicle&id=31216
The EPA doesn’t figure in gas with ethanol. Then the government forces us to use ethanol, which reduces our real world MPG.
Ohh good call @goldwing I did not know that, but it makes sence !
From Fueleconomy.gov
Do EPA fuel economy estimates account for the use of ethanol blends that are common today?
No. The EPA fuel economy tests use 100 percent gasoline, and no adjustments are made to account for ethanol. Most conventional vehicles using E10 (10 percent ethanol) will experience a 3 to 4 percent reduction in fuel economy.
I can’t verify this but I believe that the EPA numbers are from using non-ethanol gasoline. Are you using 10% ethanol gasoline? I have had continuous access to both and I can tell you that the 10% blend will result in lower gas mileage. The EPA numbers that you see have been adopted as official government numbers but are submitted by the mfr and spot checked by the EPA. Check your mileage over a few fills as the fill point where the pump shuts off can vary.
I remember reading an article by Tom Mccahill where a friend who was a dealer had a customer who complained that his new car, purchased from the dealer, didn’t get the advertised mileage. Tom took the customer out for a ride in the customer’s car. Tom got almost the identical mileage as that which was advertised. At the end of the ride when the customer saw the fuel mileage that McCahill obtained, the customer said, "Who wants to drive like that all the time?"
When I purchase a car, I establish a baseline gasoline mileage. I do make certain that the tires are inflated to the proper temperature and that the thermostat is doing its job. I monitor the gasoline mileage. If it goes down drastically from the baseline, I then look for a problem. Just recently on my 2011 Toyota Sienna, the mileage has gone up about 3 mpg above my baseline for town driving. I was first going to give credit to the brand of gasoline that I purchased. However, upon reflection, I haven’t had to use the air conditioning for the last couple of weeks. When my son first got his driver’s license as a teen-ager, he always obtained better mileage on the Ford Aerostar van that we had than either my wife or I could get. He reasoned that the Aerostar liked him better than either of us. The real reason is that he is very laid back and a non-aggressive driver and was never in a hurry to get anyplace. Driving habits make a big difference.
I wish you had read this forum before you bought the car. i wish I had. The cars mileage is a total rip off. I tried doing lemon law and was shot down due to gas mileage not being covered. Hyundai is totally misleading their customers. check out California they are doinga class action law suit against hyundai. Have you seen the website www.my2012elantragetslousygasmileage.com? great website.
The EPA puts the car on a dynamometer inside a building and tests it using the exact same conditions they use for any car. If it makes you feel any better, you would never get anything close to the expected mileage with any car. The EPA mileage is often close to what someone might get, but is really meant for comparison shopping.
Are you basing your mileage on your own calculations, or those shown on the dash? I have a 2013 Elantra, and am getting the mileage advertised (around 30 for city, so a bit low, but over 40 on highway) based on the mileage shown on the dash.
I’m going to do my own calculations next time I fill up.
Oops ! The Check’s In The Mail !
How About Some Money From Hyundai ?
Stop By The Dealer Once In A While And Check Your MailBox.
The story is out there today. I just read it on the front page of The Detroit News (11/2/2012).
http://www.detroitnews.com/article/20121102/AUTO0104/211020372/Hyundai-Kia-misstate-mileage-claims?odyssey=tab|topnews|text|FRONTPAGE
CSA
Just out today in the news…
Hyundai and Kia overestimated their fuel economy on 900,000 US vehicles sold in the US.