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Hyundai Sonata Real World MPG



  • bhmr59bhmr59 Posts: 1,598
    Craig, your compter may not be off. A pint or less of gas difference in one fill up can lead to the differences you have notices.

    A manual calculation based on 1,000 or 1,500 miles will give a more accurate reading than a trip of 400 miles
  • Good point! I never thought of that.
  • podpod Posts: 176
    edited September 2010
    Actually a pint over 15 gallons is 1/120=0.66% error which is small. I suspect that the circumstances of each tankfull vary sufficiently to account for 0.5-4.5 mpg per tankful. Was it hilly, stop and go in part, very cold, very hot, were you in a hurry, was it raining, etc. The prime MPG seems to occur when the car is in 6th gear but not being whipped. I have a Mercury Milan 2010 which has given between 32-33 mpg since new in mixed driving. Actually slower driving where the lower gears hang on is not very fuel efficient at all. Thus I agree with the recommendation that the longer the interval under scrutiny, the more such variations will tend to cancel out. Any particular tankful will vary from any other. The trip computer, at least in the Milan, has been within 0.5 mpg of my calculated mpg using the odometer and fuel purchase numbers. It suggests that going about 65-67 on a flat road with the windows cracked and the a/c off (when you can sustain that speed, e.g. cruise control) the Milan I-4 will give over 40 mpg. The problem is that there is no such road or circumstance that applies over a tankful unless you are on a long trip through the midwest in the early morning when everyone else is sleeping or eating donuts. I think the ultimate mpg will settle out somewhere about 35-36mpg highway once the car loosens up a bit. I'm very pleased with the Milan which I chose over a 2010 Sonata because of the NVH difference. In the Sonata I could hear too much noise in the rear suspension even when the surface was reasonably clean.
  • bhmr59bhmr59 Posts: 1,598
    And a pint (1/8th of a gal) difference over 400 miles in a car getting approx 30 mpg will indicate a difference in calculated mpg of 0.3 mpg. Very close to some of the reported differences between computer and manually calculated mpg.

    You mixed your units of measure to arrive at a 0.66% error. While a pint is 1/8 of a gallon we were discussing miles per gallon. You figured based on one pint per 15 gallons and used that % per tankful. (1/120 = 0.83%).
  • I hate to burst everyone's bubble, but the Sonata Turbo posted mileage is a scam. I purchased a 2011 Turbo in November and have close to 1700 miles. I check the MPG via the "Trip" and manually. The difference between the two is about .5 - .75 mpg. I admit to having a heavy foot, but I had the same foot driving my 2000 Lexus RX300. Would you believe I get the same gas mileage. I am averaging 16-18 mpg driving a 70/30 city/hwy mix. I am so upset because I was going to buy the non-turbo but the guy convinced me the mileage difference was negligible. I then heard Costco gas could be the culprit. So I drove until empty and added an octane booster along with Unocal 76 89 octane. I have been using Unocal since and my mileage actually went up, but only about 1.5 mpg. I know it is not just me because I have a friend at work who purchased the Turbo and he is averaging 20mpg with mixed driving. All the new cars I purchased in the past usually averaged between the posted sticker mileage. This is the first vehicle in 30 years of driving that is so far off base. I am actually contemplating taking action against Hyundai. I would like to hear if anyone else purchased a Turbo and is having the same poor fuel economy.
    With only 1700 miles on the car I would not really call on the big guns just yet. Why don't you first wait til after the first oil change and change where you get your gas, use Shell or BP gas, then let us know want your getting. I've never heard of Unocal 76 and maybe they way they treat their fuel is not agreeing with the car's engineering. And if after the first oil change your still getting 16-18mpg, consult with your nearest dealer.

    By the way. You do know that if your vehicle is getting anywhere within the specified range that's in the fine print on the Maroney Label under the big numbers, that they will tell you it's operating to factory specs. I had tell that to a customer and they just didn't believe me.
  • dudleyrdudleyr Posts: 3,426
    The dealer lied. The turbo will only get close to the na cars mpg if it is driven conservatively. Get into the boost a lot and mpg will suffer.
  • I do not own a Turbo, I have a 2011 Sonata Limited and I am experiencing awful gas mileage, 18.75 mpg/city driving. I don't do much highway driving for an extended length of time but I would have certainly thought I would get better mileage. I had previously owned a 2003 Toyota Camry and averaged 23/city. I am quite upset, will be meeting with Regional Rep from Hyundai, I hope, but I don't know what to expect since the sticker is: quote "an estimate".

    Anybody else having same mileage issues?

  • fushigifushigi Posts: 1,232
    Well, right now most of the US is on winter-blend gas which is a reformulation that is supposed to be more emissions-friendly in cold weather. Downside is most folks see a 2-3MPG falloff in their fuel economy. So that might be part of your problem.

    There are other things to check to make sure the care is best positioned to maximize fuel economy. Things like making sure all tires are properly inflated, making sure the air filter isn't clogged, etc. You might also try a couple of tanks of gas from a top tier supplier ( ) in case your current supplier isn't giving you a quality product.

    EPA estimate is 22 city so you're only 3.25 MPG off. That could be due to winter gas, driving style, and your version of city driving (which may differ from my version and from the EPA's version). For instance, I call city driving anything non-highway. But I live in the suburbs and often can go for nice stretches at 40-45 MPH where my car is near peak efficiency.
  • hyundailemon1hyundailemon1 Posts: 9
    edited February 2011
    My wife and I have over 700 miles on the car. We drive it about 70% surburban (not city) and 30. We are very conservative drivers, accellerating and braking very gently we don't speed, never exceeding the speed limit by 10%. It is mostly used with temperatures in the 30s. We use brand name gasoline of the recommended octane. The air conditioner is never on and the windows are closed choosing instead to use the car's filtered air coming through the vents. We never tow anything behind the car, the trunk never has more than a few bags of groceries and at most there is one adult and one toddler passenger. The tires are at 32psi.The car never idles more than 30 seconds except perhaps at traffic signals.

    I think I have addressed all the mpg variables above. My wife and I are achieving 13.x mpg, all types of driving combined. We have used several different methods to measure mileage. Hyundai used their own unrealistically conservative test and got 16 mpg.

    They will do nothing about this because the car "is operating within design parameters". I have gone up the chain of command even at the corporate level and have been basically told "mileage may vary" and I "have no recourse".

    Anybody else with a similar horror story, either the mileage or their refusal to fix an obvious defect?
  • nj2pa2ncnj2pa2nc Posts: 813
    wow that is not very good-we also own a '11 sonata GLS but with manual transmission. We average over 30 MPG. The best so far has been 37.6 doing highway driving with the cruise control on. (5 over speed limit) Speed limit on the highway near us is 70 MPH. Our sonata, bought 7/10, has 11,000+ miles
  • jlindhjlindh Posts: 282
    Sounds to me like there is something seriously wrong. Could be your driving, but more likely the car. The car will get better mileage when fully broken in, but that still doesn't explain the mileage you're getting now. Do you have a trusted relative or friend that gets good gas mileage in their car? You might swap for a few days and see how they do. You might also try to get a loaner from your dealer and see how you do with that. Or, you might rent a Sonata and see how you do with that one.

    This isn't going to cure your problem, but you should be able to figure out where the problem lies.
  • I just bought my car last week and am below 400 miles, but my mileage is not much better than 20 mpg. However I think I have a bigger problem. The car I test drove seemed like a real screamer and threw my head against the head rest when I buried the accelerator. That instantly made me want the car. I was nice to my car during the pre-purchase test drive since I was actually going to buy the car and didn't want to abuse it before the break in. After purchasing, I buried the accelerator on my car and it didn't jump like the test drive car. I don't know if the car is acting normal or if I have a lemon. It just feels like a it is missing about 100 hp. It gets up to 80 mph fast enough to be hang with freeway traffic, but I paid for 274 hp and I want 274 hp. I would like to know other owners' 30-60 mph acceleration time and the general behind the wheel feeling. .
  • My parents bought the 2011 Sonata 2 weeks before we did and are getting twice the mileage.

    In terms of driving style we drive conservatively. In fact on the highway where the limit is 55 we don't drive faster than 63 mph, and then we got <23mpg. The EPA statistics Hyundai so fondly embraces and promotes, are for 22mpg in the city and 35 mpg on the highway. The reals world results found at the EPA website: <a href="" target="_blank"> e&details=on give an accurate picture of how insincere Hyundai is when they tell me 16 mpg is within design parameters.
  • backybacky Twin CitiesPosts: 18,682
    The other test you could do, pretty easily, is remove as many variables as possible. Find a stretch of highway that runs 10 or more miles w/o stops, and preferably over flat terrain. Choose a time of day when you can drive at a constant speed -- maybe on a weekend. If there is any kind of wind, do the test in both directions. The warmer the day, the better--don't choose a day much below freezing. Check that the tire pressures are to spec, warm up the engine, get up to highway speed (at the posted speed), then reset the mpg meter. Set the cruise control if you have trouble maintaining constant speed with a light foot on the gas. If this test doesn't achieve over 30 mpg (and it should be mid-30s at least if the speed is under 70), I think there's something wrong. If it does get that kind of fuel economy, then I think you need to look closely at how you drive, including idle time (at 0 mpg), pressure on the gas pedal, and average speed (which the Sonata measures, right?).

    The idea about swapping your car, e.g. swap Sonatas with your parents, is a good one. If they get poor fuel economy while driving your car, and you get much better fuel economy driving their car, that will tell you a lot. But if they get good fuel economy while driving your car... that will tell you a lot also.
  • jlindhjlindh Posts: 282
    Perfect, swap cars with your parents for a few weeks. Keep excellent records. Give your local dealer and Hyundai Corporate the results. If the results are as far out of whack as I suspect they might be, you should get some action from Hyundai. You have a perfect Lemon Law case if Hyundai cannot rectify the situation after you take the car in X number of times for repair. X will vary depending on your states' Lemon Law. Fifty percent less mileage can't be within specs, that's ridiculous.

    By the way, awful is spelled AWFUL, aweful would be something else.
  • hyundailemon1hyundailemon1 Posts: 9
    edited February 2011
    Interestingly the numbers Hyundai achieved on their unrealistically CONSERVATIVE test were16 mpg "city" (and 22 highway). There were no cold starts, no stop and go traffic and little braking approaching stop signs, therefore little loss of kinetic energy/ wasted consumption of fuel. We coasted into stop signs at 2-3 mph

    Hyundai has at various corporate levels told me the figures are within design parameters.

    They have refused to "fix" the car because as far as they are concerned there is nothing wrong with the car. I am left only with pursuing the liberal New York State Lemon Law. I thought and still somehow hope Hyundai would, in the face of such a blatant defect, NOT tell me and the public, as I share my story of terrible mileage don't expect much of the 2011 Sonata. I continue to spread the word hoping the attention I get will "persuade" them to do the right thing. :mad: :lemon: :lemon: :lemon:
  • Swapping Sonatas with my parents is implausible since they live in Florida and we live in New York. However, as an example of our driving style my wife's 1995 civic still gets 27 mpg average and my 2004 civic gets 34 mpg average. The 2004's mpg has been calculated over the course every tank of gas since I bought the car 6.5 years ago. I am obsessive about it so when I share with you that we are very conservative drivers its based on very good record keeping.
  • backybacky Twin CitiesPosts: 18,682
    So the temperature difference between NY and FL will account for some of the discrepancy.

    How about renting a Sonata for a day or two, and driving it as you would your car? That would also provide evidence to Hyundai and/or lemon law officials that there is something wrong with your car--if the rental does a lot better than your car, under the same conditions.

    How about trying the highway test I suggested? That would take little time, and provide further evidence.
  • hyundailemon1hyundailemon1 Posts: 9
    edited February 2011
    Every drop of gas since I bought the Sonata has been documented and I have receipts for same along with photos of the odometer and the avg. mpg display along with notes about driving type (city or highway or mix) and photos of the odometer and avg. mpg as it may have changed a bit since the last trip.

    My average of 13.x mpg is well documented. The dealership service manager said of his city driving test of 2 miles he achieved 23.8 mpg. When I arrived home (exactly 5 miles) the avg mpg, having been reset before he ran the test, went down to 13.4 mpg. Their alleged 23.8 mpg "result" is written on the dealership's work order. In order for the avg mpg to have dove from 23.8 to 13.4 mpg, the Sonata must have averaged 9.x mpg for the trip home.

    Hyundai corporate had absolutely no interest in this falsified information even though Star Hyundai is their agent. I don't understand what's wrong with the Hyundai people. :confuse:
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