Regarding petrol consumption of the Hyundai Sonata being considerably less good than the ads claim, it could be something to do with a facility which I have on my Nissan Maxima QX. The overdrive can be switched on and off using a button on the gear selector. If the overdrive is off you will only ever get to 3rd gear instead of 4th and so the car will drink petrol at higher speeds. I guess you will already have checked this out, but I thought it might be worth mentioning. Cheers, Matthew.
You're supposed to have the overdrive off when driving under about 40 MPH. That's why it's called 'Overdrive' because it's for highway travel. I don't think that has too much to do with the fuel mileage though.
You should leave overdrive "on" all the time. The car knows when overdrive is appropriate and will only engage it around 40mph and above. If you want to override it for some reason, just turn it off. I've never come across the need to do this, though.
I have an 07' V6 Sonata, and the gas consumption is exactly what Hyundai states. I've driven it 15000km in 4 months and I've had no problems at all.
Most cars do not get the mileage that is stated by the EPA, also when you read the little disclosure it depends how and where you drive, the most my car got was 24.9 mpg on the highway which is good for a car size and it has V6 power, I get the best mileage by using cruise control, it takes a while to get good gas mileage it can take as long 10-20k miles for the car to break in.
In Dec 06 we purchased our second Hyundai vehicle, the new one is a Sonata 07. The dealer replaced the shocks almost immediately as we complained about the rough and noisy ride. A service tech rode with us just this week (April 07) and could hear and feel the noise from "under" the car. The service tech talked to Hyundai in Ca and there is nothing they will do any further for the rough and noisy ride. No more Hyundai's for us.
The 33 mpg stated for the Sonata is pure fantasy and it's fantastic how they can lie like this. My highway mpg is at best 28. That's W/O aircon and just me in the car besides the egg that I'm wearing under my right foot.
But by now I'm so used to advertising lying that I don't hardly react anymore. Hyundai is not any worse that the rest of the bunch out there.
Hyundai does not generate their mileage claims, your federal government (the EPA) does. The same is true for all manufacturers. They test and design their own vehicles, and they may even design the vehicle to perform better in the test than in real world driving, but the numbers come from the EPA, and that is the ONLY mileage figures the manufacturer is allowed to advertise.
If you want to know more, read this: http://www.fueleconomy.gov/feg/info.shtml#estimates
Bought an 4-cyl, auto '07 GLS 30 June. 1 July (yesterday) we drove it for about 204 miles, about 1/2 2-lane country roads and 1/2 Interstate. (Logan, Garden City, Evanston, Park City, Salt Lake City.)
This is in mountainous country in a heatwave, so we ran the A/C the whole way. We also got stuck in stop-n-go traffic for several miles due to construction. Speed limit on the freeway segment was 75 - 65 MPH, dropping as we got closer to Salt Lake City. I ran about 5 over whatever the limit was much of the time, and somewhat under it some of the time. (Did I mention there were lots of twisty mountain roads? <g>)
We got 30.2 MPG on the trip. Car had about 170 miles on it when delivered to us. Given the circumstances, I am pleased with the mileage on its maiden voyage. Hope you get yours to give you the satisfaction mine is giving me.
The mileage will get better as the engine breaks in. When I first bought mine the best hwy mpg I could get was around 29. Now, just this last week I got 33.9mpg with the cruise on 75 on a trip from Birmingham, AL to Indianapolis, IN. I just turned over 24000 miles on my 2007 4 cyl. automatic. It will get better trust me!