I supposed you’d have to show what kind of gas mileage you were getting and what the driving conditions were. Factory tires vs. aftermarket. Hard accelerating. City vs. higway. If highway nothing over 70mph. Windows closed. A/C not running. Ice/Snow vs. dry pavement. What type of gasoline.
What type of gas mileage are you getting vs. what the sticker says?
My Yukon Denali SUV was rated 12 (city) - 17 (highway) and despite considerable highway driving it 's average mileage (thanks to the fancy onboard computer tracking) is 12.5 mpg. I talked to the dealership about this crappy mileage but the overwheming response was a yawn and a suggestion for a paid maintenance update.
The impression I get in talking to large American truck SUV owners is that big (gas engine) truck number ranges are a borderline lie, and will always tend strongly toward the lower numbers.
Unless there’s a fuel system problem you’re pretty much stuck.
How did you determine that there’s nothing wrong with the truck?
Also, are you driving the way you are supposed to - i.e. accelerating gently, keeping your speed below the posted limit, shifting at prescribed RPM (if it’s a stickshift), checking the tire pressures periodically, etc.? If not, the only person you can blame is yourself.
Is it still under warranty?
Before I sued anybody I would contact the dealer or zone rep and ask them to check it out from stem to stern to verify that everything is really “okay”. I would think they could put it on a Dynamometer and check on the engine’s efficiency etc. It could be something as simple as a stuck emergency brake.
Is the check engine light on?
Do you happen to drive in a manner that might worsen your mileage (fast starts and stops, high speed etc.)?
The sticker estimates are 13/17 (city/highway). I’m getting more like 10.
I’m not an aggressive driver. Most of my driving is highway (Long Island Expressway, right lane, not usually above 65 mph). Terrain is not an issue (most folks would tell you most of Long Island is flatter than Callista Flockhart.) I bought the truck at the end of last summer and A/C really hasn’t been used much. I have the factory rims and tires, and I check the pressure frequently with a digital gauge.
The truck has 13,500 miles on it. I change the oil myself with the recommended oil every 3,000 miles. I used the recommended octane (89) - no more, no less.
According to our friend the walrus, looks like I’d have to drive like my grandfather if I wanted to match the test conditions. But still, should gas mileage be this far below posted sticker estimates? What’s the purpose of having the estimates in the first place if they’re going to be so far off?
The way I’ve had it explained to me is that the EPA estimates for a specific car will always be higher than what you will get driving under normal conditions. However, they are valuable as a comparison between different makes/models/configurations while shopping for a vehicle.
The mileage is calculated under laboratory conditions, which are not very realistic. But they are stable and identical for every car tested. So the numbers are a good way to compare different cars.Even if you never get the same efficiency as the lab test, you can know before you buy how your car compares to other models.
It’s better than taking a salesman’s word for it.
Hee. Reminds me of the 36 mpg Ford Hybrid Escape they’re advertising. Like fun you get 36 mpg. I’ve got one of those (identical to the one pictured in the ad) and we don’t get anywhere near 36 mpg. At the end of October (when it was still warmish), SpouseO reported a high of 29 mpg. This winter, it’s dropped to about 24 - 25ish. Which is still not bad, but not nearly as good as they’re claiming, either. His mpg will climb again as it warms up, but I’m doubting it’ll hit their numbers.
But their numbers are inflated due to the testing conditions, as others have stated. We’re just happy that it’s so much better than the 18 or so mpg his old SUV got.
Back in the 80’s we used to get two kinds of complaints on the first service on new cars. People with turbos complained about poor gas mileage, and people with non-turbos complained about no power.
Cars now have way more power then cars back in the 80s. This means that it is very easy to get gas mileage that is way less than the numbers posted on the window, and very hard to get as good or better.
You admit to going 65 which puts above the speed that the test is run at and increases the wind resistance a bunch. You are also driving a truck vs. the Vette which makes the wind resistance penalty much worse.
As important as your speed (or maybe more so) just how you drive. I can take a car and get way less than 1/2 of the estimated mileage or just a little over all based on how I drive the car.
When driving on the freeway are you on and off the gas? I know some people that treat the gas pedal like a digital switch on or off, no part way. Needless to say their gas mileage sucks. do you step on the brakes often? Every time you step on the brake you cost yourself gas mileage. One big trick to improving gas mileage is to look way down the road. if you see a stop light that is read a block ahead take your foot off the gas and coast. Same applies to the freeway. If you see yourself catching up with the guy in front, take your foot off the gas and coast up to match his speed. Don’t roar up and step on the brake. To get max gas mileage you have to accelerate very slowly. The quote that iamthewalrus provides says 0-60 in 18 seconds. Many cars can do it in a little over 1/3 of that time. The problem is it costs a bunch of gas to do that. if your truck has a trip computer, set it to read instantaneous and try to keep that number as high as possible.
I make it a hobby to see just how high a gas mileage number I can record in the cars I drive. The car I am currently in has EPA numbers of 21/28. Over the weekend I got about 20.5 in town, and have seen 32 on the highway. This car only has about 1,000miles on it so I expect these numbers to increase as the engine breaks in. So you can exceed the EPA numbers, but it takes some work.
Check the Consumer Reports review of your model (should have issues at your library). If their figure is clearly different from what you are getting, then there might be something actually wrong. (I’d look it up for you but you didn’t give the year and model.)
The EPA “estimates” are a joke. There are heavily gamed by the makers who don’t even submit actual production models for testing.
There are also going to be factors that are totally out of your control.
Example: I live in Minnesota. If I drive to Iowa, and fill up my gas tank there, I see an increase of 4-5 mpg. It’s not just one gas station in Minnesota vs one in Iowa, it really does seem to be all of them. My guess is that Minnesota’s ethanol content requirement does this, but that’s just a WAG. Either way, things like the gas you are using could also seriously impact your milage.
I can beat my car’s fuel economy ratings in both city and highway driving.
On surface streets I use moderate (let’s say 20%). I lift up whenever my car hits 2200 RPM or so in order that it will shift up to the next gear.
When I get to 25, I stabilize my speed. When I see a red light up ahead I immediately get off of the gas. If I do have to brake for the light, I’ll usually have coasted down to 10-15 MPH by the time I get there. Same thing for traffic; if I’m within 6 car-lengths of the guy ahead, I’m going too fast. On city streets, speeds over 25 just mean I’ll be doing that much more braking when I get cut off or hit a light. I don’t use my brakes a lot in this mode.
On the on-ramp I use a judicious amount (let’s say 40%) of gas on the flat lead-up to the ramp, again backing off of the gas to encourage upshifting as appropriate. When I hit the uphill part of the ramp, I just hold my speed; I will not accelerate there. Once I’m on a flat or downhill segment, I’ll finish getting up to speed. I won’t exceed 2500 RPM on the on-ramp under any circumstances and I can keep under 2200 RPM if I don’t have to worry about merging.
When cruising, I’ll tool along at 55 on the flats or uphill. If there’s a downhill, I’ll keep my gas at the “flat highway” setting until I hit 60, then I’ll back off. If I’m going 60 when I hit the flats or a hill, I let the car drop to 55 before I use the gas enough to maintain my speed.
If you get within 6 car-lengths of my front end on the highway, I’ll slow down until it’s 8 car-lengths.
I can ALWAYS beat the EPA estimates this way, unless the roads in question have too much traffic or TOO MANY stop signs and red lights.
About my throttle settings above: my car is a mid-sized sedan making 200 HP. By today’s standards that’s normal, but it is fairly overpowered for the job of propelling me to work at 55 MPH. This is why I call 40% judicious on the on-ramp. It’s more than strictly needed, but it works for my plan.
I don’t drive the way I just described all the time, but when traffic is light enough that it’s not impolite and I have no urgency to arrive at my destination, I do it.
My car is rated at 20 city and 30 highway. I can get 23 city and 33 highway all day long if I stick to the driving style I just described.
Also, I lose about 10% of my gas mileage when Ohio uses “winter” gas. The OP might want to consider that when calculating his mileage.
I’ve heard but have not confirmed that some makes of cars have onboard computers that are designed specifically to recognise the EPA test run driving sequence and to switch to a particularly fuel efficient mode for the duration of the test. Anybody care to confirm or deny?