Gas mileage

venram1venram1 Member Posts: 4
edited April 2014 in Toyota
I've a 98 Corolla with 6700 miles on it. It still
doesn't give me the gas mileages posted on edmund's
site(28 in the city and 36 on the highway).
Recently I drove to a place 100 miles from Austin.
I was on cruise for the most part of the trip. I
got only about 31 mpg !!! I used to own a 96 Saturn
SL1 which used to give me more than 40mpg with
cruise on the highway.

So, is this something I need to check with the
dealer right away ? What could have possibly gone
wrong with the car ?

I already talked to a dealer over the phone once.
They mentioned that the 28/36 mileages were under
ideal conditions and the actuals may vary with
driving conditions etc. etc.

Thanks in advance for any feed back.



  • roscoeroscoe Member Posts: 1
    I am considering buying a 1999 F-250 Super Duty, supercab with an automatic transmission and four wheel drive. I have found reviews that give the mileage for the V-10 but I have not seen a review with the V-8. Does anybody know what kind of mileage the V-8 would deliver?
  • jonyen98jonyen98 Member Posts: 6

    I bought a 99 corolla a month ago. At the first fill-up, I calculated 26.7mpg (mostly non-peak hours on Los Angeles freeways). I was told that a brand new car will not get it's optimum gas mileage. My 2nd, 3rd, and 4th fill-up were 35.5,
    35.2, and 31.5 mpg respectively.

    If you read the window sticker of the corolla, it will say in big prints 28/36 city/highway. But in the small print it says that actual mileage will vary with options, driving conditions, driver habit, and vehicle condition. It also says in small print that most cars in this class will achieve 23-33mpg in the city, and 30-42mpg on the highway.

    What do you usuall average on your corolla? 31mpg is not great, but it's also not all that bad. When you compare the mileage of your Saturn to your Corolla, are the conditions the same? For example: the load you're carrying, traffic, hills, etc.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,482
    Dear VEn,

    I'd say it's about as good as it's going to get,and 31 mpg is quite good. There's nothing wrong with the car. You might gain some improvement by checking tire pressure and inflating to maximum, using synthetic oil for faster warmups (less time on rich settings) and paying attention to driving habits. For instance, cruise control can often decrease mileage (LKF---little known fact). I'd say if you did all those three things, you could gain 1-2 mpg. Otherwise, be content, it's within specs.
  • venram1venram1 Member Posts: 4
    Thanks for all your feedback. Jonyen98, the driving conditions of my Saturn are the same as the current Corolla I own. The fact that cruise control can often decrease mileage, really surprised me.
  • guitarzanguitarzan Member Posts: 868
    Gas mileage is a function of how far the accelerator is depressed. If you are in your top gear on the highway, using cruise control, and encounter a hill, the gas pedal goes way down. If you're in a stick shift, you can downshift, and perhaps lift up on the gas greatly. Also, if the freeway is hilly, using a downhill slope to speed the car up a little to prepare for the next uphill slope helps save gas too. Just a few instances where the cruise may not be as efficient as the driver.
  • dmattgamdmattgam Member Posts: 15

    I always thought that cruise control gives you better mileage until I read the last few posts. From what you said, it sounds as if cruise control works OK if the highway is flat and not hilly at all.

    I also have another question regarding mileage on my 1999 LS400. I had a 1998 ES300 for about a year before trading it in for the 1999 LS400. For the one year that I owned the ES300, I got very good mileage with the car i.e. 25 MPG overall which is the same as or 1 mile off the sticker of the 1998 ES300.

    I have the LS400 for about 2 months now. So far, I only got about 21 MPG at best (about 3 or 4 miles off the sticker's of the car). I haven't changed my driving habit nor the route that I take to go to work. Any idea why this is the case ? Thanks.
  • guitarzanguitarzan Member Posts: 868
    I'd give it some time, first of all. The computer may need to learn your driving habits (just a guess, I don't know this for fact). Also, higher end cars typically have harder rings that take 10k miles or more to seat perfectly. Sorry, but I'm too lazy to check the weights and power capability of each of those cars. Are they similar, or is the LS much more powerful? Give it some time, in any case, and please report back.

    If I had such a car, I wouldn't even look at the gas figures. The "fun" part of it would erase any passing thoughts of economy.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,482
    Remember, dmattgam, you have two more mouths to feed now.
  • dmattgamdmattgam Member Posts: 15
    OK, Mr. Shiftright, I'll mark on my calendar two months from now to remind me. I'll report what I find after putting on a few thousand miles on my car.
  • ylockheadylockhead Member Posts: 10
    Temperature can affect the mileage. So can atmospheric pressure. I've read somewhere that the higher the atmospheric pressure, the better the gaz mileage (it has to do with the density of the air). When the air is denser, the engine can 'breath in' a larger amount of air, providing a better combustion. I wonder if this is still valid for a moderm car that is all computerized? What I am sure about is that extremely low temperatures (-20) have an adverse affect of mileage. It would be fun to know under what conditions the mileage reported by a manufacturer is obtained. My guess is it's done with no head wind, higher atmospheric pressure and at temperature around 70-80 degrees.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,482
    Oh, yeah, the higher the altitude the lower the fuel mileage and the power....having a turbo helps this somewhat however.

    Manufacturer's use some kind of test cycle to determine mileage, and yes, it's under fairly ideal conditions.

    How you drive counts for a lot.. I have a standing bet with friends that i can get better gas mileage from their car then they radical tricks, shutting off the engine or coasting...just driving in your bare feet would help a little actually, but i don't recommend it on snowy days....tire pressure is very important too, and hardly anyone thinks of that...
  • KCRamKCRam Member Posts: 3,516

    THe mileage figures you see reported (from the EPA) are conducted in a lab that is set for "ideal" atmospheric conditions. In fact, it's not even a test for mileage. It's a fuel usage analysis based on the amount of emissions from the tailpipe. This is why you are always warned to use EPA figures for comparison only, and not to expect that mileage from the vehicle you drive. Because of public outcry that the numbers were unrealistic, the EPA even reduces the "public" figures.

    Here is the number calculation that is used - we'll use a 1999 "Edmund SE" sedan :)

    EPA test results by emissions analysis:
    26 mpg city
    38 mpg highway

    The EPA combined figure that tha manufacturer uses for their Corporate Average Fuel Economy (CAFE):
    2/3 city + 1/3 highway = 30 mpg

    The EPA "public" figures - what you see on the sticker:
    90% of city - 23 mpg
    78% of highway - 30 mpg
  • KCRamKCRam Member Posts: 3,516
    oh, one thing to add: the city test is conducted at an average speed of 25 mph, the highway test is conducted at an average sped of 49 mph. Since the majority of us drive 65+ on the highway, you will probably never see the original highway number on an open road.

    In my example above, you can see that Edmunds can sell all the SE sedans they want, because the combined mpg figure is well above the CAFE requirement of 27.5 mpg. They can thus sell an equal number of cars that only get a combined value of 25 mpg. The truck CAFE is only 20.7 mpg - this is why you see so many V6 and V8 SUVs - they are balanced by 4 and 6 cylinder mini-trucks.
  • shiposhipo Member Posts: 9,148
    In 1986, I was driving a 1985 Dodge Daytona Turbo from Chicago to Las Vegas. I stopped for the night in Council Bluffs, IA. The next morning, it was -15 degrees outside. I filled up in Omaha, NE, set the cruise control and drove non stop to Denver, CO! If I remember correctly, that was a distance of about 525 miles, on a single tank of gas. When I filled up in Denver, the car took less than 13 gallons of gas, it worked out to something like 42 mpg. I was stunned, prior to that tank, I had never gotten more that 400 miles on any single tank of gas.

    The next year I tried it again, it was ONLY about 10 degrees during the 1987 trip. I filled up in Omaha, set the cruise control and made it almost to Denver (I think that tank yielded about 510 miles). The only way I have been able to rationalize getting 25% better mileage on those two tanks was a combination of the following:
    1) Altitude, less wind resistance against the car (running at a steady 70mph).
    2) Turbo, while the air outside the engine was thinner, the turbo kept the air pressure inside "just right".
    3) Cold air, I have had two turbo cars, and they were always faster and got better mileage in cold weather. I assume that because of the cold(er) charge entering the intake manifold, the computer was able to keep the engine settings a little more aggressive than at warmer temperatures.

  • Mr_ShiftrightMr_Shiftright Member Posts: 64,482
    Some of what you say makes good sense, but not the altitude part if I'm reading you right...altitude should make the mileage worse. A good tailwind wouldn't hurt you either. It's hard to judge real mileage the way you were doing it, since you really need to have the car perfectly at the level (a slight tilt could throw you off two gallons easy) and you need to average it out over ten or twenty fill ups. But still it sounds like a good run for a car like that.
  • shiposhipo Member Posts: 9,148
    In a normally aspirated engine, altitude will certainly decrease fuel economy. In a car equipped with a turbo engine, moderate altitude (in the case of my Omaha to Denver runs, between 3000' and 5000') may in fact increase mileage.

    I am not a physicist, but I have studied the basic physics of a turbo charged engine. Maybe I have this all wrong, but based upon what I have learned about turbo charged engines, there is virtually no loss of power (just slightly more turbo lag) at moderate altitudes. At any given steady speed, the turbine will spin faster at moderate altitude vs. sea level keeping the intake manifold pressure virtually the same. In essence, down stream of the turbo, the engine will operate at virtually the same efficiency as at sea level. That being the case, with the engine producing power just as efficiently as always but with less dense air to push the car's body through, the vehicle should get better mileage.

    Did I miss something?

  • Mr_ShiftrightMr_Shiftright Member Posts: 64,482
    Well, he did say Denver, which is the Mile High City....but I was only relating my experience with my turbo car...the higher it went, the lower the fuel mileage, but I could agree that at a few thousand feet there wouldn't be much, if any difference...I'd buy that, but over 5,000 ft, I'd have to say that there's a loss of power even with a turbo, although much less than with an non-turbo car. I recall at 11,000 feet how many of the big engines really struggled.
  • shiposhipo Member Posts: 9,148

    I took both of my turbo cars up to around 12,000 (Loveland and Independence) and you are totally correct, lower mileage and power, BUT not as much as a normally aspirated car with a similar power rating.

    Both of my cars had boost gauges on the dash, it was very interesting to watch as the gauge would ever so slowly move it's way up the scale as the turbine would claw for every molecule of air it could find. Talk about "Turbo Lag" WOW, it seemed like it would take a full minute for the turbo to get wound up at very high altitude.

    Ahhhh, the good old days, now I commute in NYC traffic every day :-(.

  • markbuckmarkbuck Member Posts: 1,021
    Turbo engines normally have lower compression, so... if you are not in the boost (cruising at moderate throttle settings) your car could suffer even more at high altitudes. I live at 7,000 in Arizona and we have 20% less air pressure. When WFO, the turbo motor definately perform better, but at light throttle settings they seem worse. Also, peak horsepower and peak torque on naturally aspirated motors move to higher rpms at higher altitudes.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,482
    Yep, that's right...I always used to keep my engine wound up when at those extreme altitudes, to stay on boost as much as possible while Saab was a dog below 2500 rpms even at sea level.
  • rdeschenerdeschene Member Posts: 331
    Just my experience:
    -maintain proper tire pressure, maintain the engine well, don't run the A/C, try to keep as steady a speed as is possible, when you have to accelerate do so smoothly and moderately, use the manufacturer-recommended octane rating of fuel.

    I've noticed lower gas mileage at 55 than 75mph too. Not that THAT stops me of course ;-)
  • gusgus Member Posts: 254
    I don't think that using the A/C is out of the question. I've heard that it's more economical to use the A/C at speeds above 40mph than it is to have the windows open at those speeds.
  • guitarzanguitarzan Member Posts: 868
    Funny how cruising speed in my 1980 Delta 88 was about 45, and in my Acura it's probably about that, 75. Just a guess. I've never gone above the national speed limit :P They've certainly done a great job in improving aerodynamics. Just a matter of actually trying, I think. It's a relatively new concern when looking at the entire auto history.
  • alex17alex17 Member Posts: 35
    What mileage is considered "good" or "better than average" for a mid-size SUV?
  • djstepdjstep Member Posts: 26
    There are many different things that will contribute to fuel economy. Air Temp., Altitude, Humidity, and I believe the biggest culprit is speed itself. Most of the state several years ago increased speed limits. Made a lot of people happy, cause everyone wants to get where they are going faster. The real reason for increasing speed limits was because cars were getting to good on the gas mileage. Fuel taxes per mile of highway use was going down. Up the speed limit, sell more gas, earn more tax revenue.

    I just bought a 99 Silverado and run a fuel check in it. A 458 mile trip with speeds from 40 to 65, averaging more around 50, and got 20.1 mpg. I concider this to be very good. The old truck used to get around 9.
  • mjb56mjb56 Member Posts: 170
    Want good fuel economy? Try a VW New Beetle TDI. Just filled up my first tankfull after a winter storage period and calculated 44 mpg in mostly city driving. Hard to top that, escpecially since this diesel has more than adequate power.
  • rdeschenerdeschene Member Posts: 331
    gus. I agree that A/C vs. windows open is a toss up, if not MORE favourable (i.e. better mileage) for running with an A/C. I was comparing A/C to no A/C and saw a roughly 7mpg difference. This was on a 1987 Taurus.
  • copelandukcopelanduk Member Posts: 14
    I live in England where fuel is expensive so this a real issue for us, but I still drive a 735i.

    Daimler chrysler were recently quoted (in CAR magazine of britain) that 1/7 of the fuel consumption of a car is spent keeping all of a cars electrical systems running (engine management, abs, AC, stereo, gadgets, etc..). Needless to say this is a pretty big chunk of the fuel consumption. Of course some systems are critical but using as little electrical power as possible should help. I wonder if cruise control might actually cost more fuel due to the previously stated reasons and because it uses more power than is necessary. I don't need cruise in London but it might affect some of you guys. Lets look forward to the higher voltage (more cost effective as less energy is bled off) systems of the future.
  • streetzzzzstreetzzzz Member Posts: 1
    I have a 1985 Monte Carlo SS with a 305 H.O., has a 200R4 tranny. We took a trip to Boston, NY
    last fall. I decided to use a new fuel additive that someone had told me about. By the way the car has 115,000 miles, tranny was rebuilt at 100,000 miles. It was mostly highway miles so the average was 22 mpg on the first tank ( it was premium fuel ) without the additive. I then put it in a full tank of premium fuel. At times my lead foot wife was running at speeds of 65 to 90 most of the way. The air was not on and she doesn't like the cruise. On that tank the numbers showed that the mileage was 28 mpg. Needless to say I've used it ever since, and have great results.
    street sleeper
  • kenokeno Member Posts: 6
    I own a 98 LS400 (basically the same car as the 99) with 2100 miles. The mileage you're averaging is about the same for my car also (I normally cruise about 80 MPH on the highway). However, I once tried this experiment after filling up: The commute was from Pelham, NY to Fairfield,CT (approximately 52 miles). I set the cruise at 55 MPH and drove in the slow lane. What I discovered was, that I was able to attain a highway mileage of 26.8 MPG clearly surpassing the EPA Highway mileage of 25 MPG.

    So it's possible to get the government estimated MPG ratings for that car provided that you stay within the speed limit. But , who wants to do that.
  • windowphobe6windowphobe6 Member Posts: 765
    The best mpg number I ever got from my old '75 Toyota Celica GT (may she rest in peace) was 29, southwest-bound on the Kansas Turnpike with a curio cabinet lashed to her roof. I have come to two conclusions: first, that I tend to drive more carefully - less jerkily, anyway - with a heavy load, and second, that the Celica's drag coefficient was so poor that adding a piece of furniture to the roof actually improved her aerodynamics.
  • bill1234bill1234 Member Posts: 1
    Whenever a car goes downhill, obviously it gains speed and momentum. But when the cruise control is on, it prevents the car from gaining speed and momentum, since the speed is fixed, so when the slope levels out, the engine has to burn more gas to keep up the car's speed. Unlike when cruise control is off, the car travels for some distance when the slope levels out.
  • mac24mac24 Member Posts: 3,910
    How does the cruise control prevent the vehicle gaining speed while going downhill? I understood that it was only connected to the throttle, not to the brakes as well.
  • joecarojoecaro Member Posts: 44
    It appears to me that it keeps the speed constant even when going down hill, but uses less gas. I can feel the throttle backing off. So I'm assuming its using less gas.
  • vivonavivona Member Posts: 410
    The cruise control does not operate the brakes. It keeps the car from gaining speed downhill up to a point by merely backing off on the throttle. In some cars, probably just Mitsubishi's with fuzzy-logic transmissions, the automatic transmission may sense the downhill condition and downshift to provide some engine braking.
  • shiposhipo Member Posts: 9,148
    Last summer my wife and I were forced into a mini-van due to a growing family. We got a 1998 Dodge Grand Caravan with the 3.8 litre engine and the ubiquitous Chrysler 4-Speed Automatic. While driving to West Virginia last fall for a rafting trip on the Gauley, I noticed that the transmission would actually downshift going down fairly steep hills to help maintain the speed of the van.

    I have since confirmed that all Chrysler products with that 4-Speed and Cruise Control do in fact use the transmission to help maintain speed when going downhill.

  • vivonavivona Member Posts: 410
    I rented a 1997 Dodge Intrepid two years ago to drive the mountains of Washington State. On long declines the car would speed up. It had the 4-speed A/T. I pulled the shift lever to second gear and that hardly made a difference. I pulled the lever to first and there was no change until I got to about 20MPH with the brakes and then the transmission would jerk into low and the car behind me would almost hit me. I found the Intrepid to be the worse car yet for mountain driving as far as the A/T is concerned. (Dang noisy, too) In any other car I have driven, going into second would provide a noticeable amount of engine braking. The Intrepid did not. I trust your van is much better.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,482
    There are so many factors affecting the accurate calculation of gas mileage that it's really hard to know what improvments are having what effect...I am personally highly skeptical that any fuel additive is going to give you a 25% improvement in fuel mileage. This would be the equivalent of a world miracle worth billions of dollars...all kept secret in a $4 can?...wind, throttle pressure, how you drive, tire inflation, wheel alignment, road level, altitude, accessories, weather, can all account in total for this improvement.

    Depending on terrain, yes, cruise control can give you worse gas mileage, especially on uphill runs....on the straight and level with no traffic, it will probably improve mileage.
  • gusgus Member Posts: 254
    Actually, I thought recently about the suggestion that you keep your tank 1/2 full in order to increase mileage. What struck me was how difficult it must be to calculate mileage if you don't know exactly how much gas you have in the tank. If you fill up, you have a fair, if not good, idea of how much gas you've used. You divide the miles on your trip meter by the number of gallons you've just pumped, and you're set. If you decide to go by your gas gauge, though, and put in two gallons of gas every time you think you're at a third of a tank, how do you know that you were actually at a third of a tank when you pumped those two gallons?! You're going by what the gas gauge tells you, and who says that gauge is accurate?!

    I'm tired and rambling right now. I feel like Jerry Seinfeld is eating my brain. What's the deal with that!
  • govugovu Member Posts: 62
    You'll need to average your mileage over several partial fill-ups. If you add up all of the miles and all of the gallons over a period of weeks or months, your mpg should be fairly accurate. It won't matter if you started with a full or a half-full tank.
  • formula94formula94 Member Posts: 22
    Is it true that the higher the gas grade the lower the gas mileaage.. I noticed that 93 octane gives me 1-3 mpg less the 89??
  • guitarzanguitarzan Member Posts: 868
    If your car does not need high octane, this is possible. High octane burns more thoroughly when given the time to do so. I'm not sure, but suspect if it doesn't have the time to burn, more of it might be left unburned in the cylinder, causing poor mileage. Is that right anyone?
  • alextalext Member Posts: 63
    I though higher octane always got lower mpg? Am I right?
  • guitarzanguitarzan Member Posts: 868
    No. If the car needs higher octane, say because it is running too hot from lower octane, you'll get more power and better milieage from high octane.
  • markbuckmarkbuck Member Posts: 1,021
    Yawl probably couldn't see the difference in fuel economy between high and low octane unless you ran a carefully controlled experiment over about 1,000 gallons (in an engine designed for 87 octane).

    Suspect fuel economy in an engine designed for high octane could be adversly effected by low octane fuel...... but my greater concerns would be around overheating (related to spark retard) and ping and potentially pre-ignition.
  • markbuckmarkbuck Member Posts: 1,021
    Just to check you, I checked the variability trip to trip for the first three years vs your 24.3 mpg. Yep, you did alot better, 3 stdev's better. Less than a 1% chance that it was pure luck that your fuel economy increase was pure luck.
  • ChadzChadz Member Posts: 2
    I recently purchased a 4-cyl 5-spd Accord Coupe EX, which Edmunds notes as having 400+ miles in the city. I am lucky though to achieve 300+ even with some highway driving. The car has 4000+ miles on it now. I am rarely gunning it at stoplights, nor am I driving aggressively habitually (every now and then you just have to have SOME fun). Anyone have any advice on how to increase my fual efficiency? Is it better to drive at 3000 RPM or 2000 rpm in a higher gear? is one better than the other for the engine? Also, does A/C lower the mileage significantly? Thanks alot!
  • guitarzanguitarzan Member Posts: 868
    Yes, the AC takes about 3 mpg away.

    Try Bosch platinum spark plugs. I believe they've helped a small bit for both Acura's I've had.

    The highest efficiency is achieved at the lowest rpm combined with the highest vacuum. This depends on what kind of road you're traveling. Going down hills, put it in high gear so the revs are lower. Going up hills, if you find your foot down at the floor on the accelerator, shift into lower gear to "let the tranny do more work for you."
  • ChadzChadz Member Posts: 2
    What do you mean by vacuum?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,482

    your higher mileage is probably the result of taking advantage of the lower rpm efficiency of a diesel engine. Driving this way with a gas engine might have the opposite effect, or not matter as much. I've often observed cruise control causing worse fuel mileage, since the driver gets lazy and doesn't downshift when they should.
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