# Why is my new (to me) car getting such lousy gas mileage? **URL:** \ **Category:** Factual Questions\ **Created:** [January 28, 2007, 11:47pm UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891 "2007-01-28T23:47:29Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Tess\_of\_the\_Derbyville](https://avatars.discourse-cdn.com/v4/letter/t/8dc957/32.png) [@Tess\_of\_the\_Derbyville](https://boards.straightdope.com/u/Tess_of_the_Derbyville)\ **Post date:** [January 28, 2007, 11:47pm UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/1 "2007-01-28T23:47:29Z")
I recently bought a 2002 Toyota Celica GT. I got it from a reportedly reputable dealer and it has a six month warranty. I’m happy with the car except for the gas mileage. On the first tank it averaged only 20 mpg with about one third of that on the highway, while the mileage estimate for this car is 29 city/36 highway. My regular mechanic drove it and did a quick check and found no obvious problems. As I said, it is under warranty so I will take it back to the dealer for repair. But I’m wondering, is this a simple adjustment or does the car have a major problem? ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [January 29, 2007, 12:10am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/2 "2007-01-29T00:10:40Z")
Is the weather really cold where you are right now? That will cause all cars to lose mileage, but it will improve during warmer weather… ---
**Author:** ![Tess\_of\_the\_Derbyville](https://avatars.discourse-cdn.com/v4/letter/t/8dc957/32.png) [@Tess\_of\_the\_Derbyville](https://boards.straightdope.com/u/Tess_of_the_Derbyville)\ **Post date:** [January 29, 2007, 1:23am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/3 "2007-01-29T01:23:28Z")
How cold do you mean? We’ve had a mild winter so far with tempertures mostly in the 40’s. ---
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [January 29, 2007, 1:34am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/4 "2007-01-29T01:34:54Z")
Winter gasoline’ll do it almost all the time. Just a sad fact of life. Also, those mileage estimates are EPA estimates which are often notorious for being high, especially on cars with tiny little engines that output pretty decent torque. That means, to get the performance that makes it fun to drive, you have to work that engine hard. EPA estimates don’t account for that. You’ll remarkably increase your mileage by driving like a granny. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [January 29, 2007, 1:56am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/5 "2007-01-29T01:56:41Z")
[QUOTE=Tess of the Derbyville] How cold do you mean? We’ve had a mild winter so far with tempertures mostly in the 40’s. [/QUOTE] Not as bad as here in New England, where mornings lately have been in the teens and single digits. But it will still affect mileage, which will increase in warmer months. ---
**Author:** ![Eleusis](https://avatars.discourse-cdn.com/v4/letter/e/f4b2a3/32.png) [@Eleusis](https://boards.straightdope.com/u/Eleusis)\ **Post date:** [January 29, 2007, 10:08am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/6 "2007-01-29T10:08:08Z")
Replacing the air filter might help… ---
**Author:** ![Seven](https://avatars.discourse-cdn.com/v4/letter/s/3d9bf3/32.png) [@Seven](https://boards.straightdope.com/u/Seven)\ **Post date:** [January 29, 2007, 10:27am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/7 "2007-01-29T10:27:01Z")
Did the mechanic drive the car and take a quick peak under the hood or did he inspect spark plugs, wires, caps, oil, air filters, etc? I just bought a new car and it was getting crap mileage. I replaced the plugs (which were really worn and old), wires, engine and transmission fluids, air filter and tires and damn near doubled the mileage. ---
**Author:** ![Schuyler](https://avatars.discourse-cdn.com/v4/letter/s/54ee81/32.png) [@Schuyler](https://boards.straightdope.com/u/Schuyler)\ **Post date:** [January 29, 2007, 7:36pm UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/8 "2007-01-29T19:36:38Z")
1. One tank of gas is probably not enough to get a reliable estimate of mileage. 2. Winter gas formulation (oxygenation) will reduce your mileage. 3. With the bulk of your mileage in the city, you’d only expect mileage in the high-20’s anyway (is it manual trans?), and city driving mileage is _ **highly** _ driver-dependent. Maybe give it another couple of tanks, and take it easy on the go pedal if you are trying to maximize mpg. Good luck. On preview - what **Seven** said, too. 🙂 ---
**Author:** ![Throatwarbler\_Mangrove](https://avatars.discourse-cdn.com/v4/letter/t/8c91f0/32.png) [@Throatwarbler\_Mangrove](https://boards.straightdope.com/u/Throatwarbler_Mangrove)\ **Post date:** [January 29, 2007, 7:44pm UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/9 "2007-01-29T19:44:43Z")
Buy an accurate tire pressure gauge, not the $0.50 pop top ones, and make sure your tires are properly inflated, and not worn out. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [January 29, 2007, 8:39pm UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/10 "2007-01-29T20:39:05Z")
And do you have air conditioning? ---
**Author:** ![StuffLikeThatThere](https://avatars.discourse-cdn.com/v4/letter/s/bc8723/32.png) [@StuffLikeThatThere](https://boards.straightdope.com/u/StuffLikeThatThere)\ **Post date:** [January 29, 2007, 8:49pm UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/11 "2007-01-29T20:49:03Z")
You could do what everyone else does to get fantastic gas mileage. Lie. I must attribute this to my husand’s old boss, who is the owner of a car dealership and is probably a little cynical on the subject. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [January 29, 2007, 8:57pm UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/12 "2007-01-29T20:57:30Z")
[QUOTE=Tess of the Derbyville] I recently bought a 2002 Toyota Celica GT. I got it from a reportedly reputable dealer and it has a six month warranty. I’m happy with the car except for the gas mileage. On the first tank it averaged only 20 mpg with about one third of that on the highway, while the mileage estimate for this car is 29 city/36 highway. [/QUOTE] There’s no such thing as a reputable Toyota dealer. 😛 But it sounds like you may have a problem, take it back. Winter should give you a 10% decrese, not a 1/3+ decrease. ---
**Author:** ![Pushkin](https://avatars.discourse-cdn.com/v4/letter/p/ee59a6/32.png) [@Pushkin](https://boards.straightdope.com/u/Pushkin)\ **Post date:** [January 30, 2007, 1:56pm UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/13 "2007-01-30T13:56:10Z")
Just a thought, the Celica probably has a variable valve timing engine, have you been keeping the revs high enough that it switches to the high power low MPG timing? ---
**Author:** ![crazyjoe](https://avatars.discourse-cdn.com/v4/letter/c/f14d63/32.png) [@crazyjoe](https://boards.straightdope.com/u/crazyjoe)\ **Post date:** [January 30, 2007, 3:35pm UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/14 "2007-01-30T15:35:18Z")
The “city” estimates provided by the EPA are with no accessories running and very moderate acceleration. If you’re running heat, lights, etc and getting stuck at stoplights longer and accelerating more quickly, you will get piss poor fuel economy as a result. 20 seems a little low, but those tiny toyota engines encourage you to rev them high to get any power out of them, so try altering your driving style for a bit and see what happens. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [January 31, 2007, 1:20am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/15 "2007-01-31T01:20:51Z")
[QUOTE=Balthisar] You’ll remarkably increase your mileage by driving like a granny. [/QUOTE] '99 Jeep Cherokee. If I drive 65 to 70 mph I get 18 to 21 mpg on the freeway. If I drive 55 to 60 mph, I get 25 mpg. ---
**Author:** ![TristanVT](https://avatars.discourse-cdn.com/v4/letter/t/a6a055/32.png) [@TristanVT](https://boards.straightdope.com/u/TristanVT)\ **Post date:** [January 31, 2007, 1:42am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/16 "2007-01-31T01:42:37Z")
Vacuum leak? ---
**Author:** ![Rigamarole](https://avatars.discourse-cdn.com/v4/letter/r/77aa72/32.png) [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)\ **Post date:** [January 31, 2007, 3:37am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/17 "2007-01-31T03:37:18Z")
I have no faith in the EPA estimates at all. My **brand new** Mazda3 is rated at 26 city / 34 highway and I have consistently averaged 21-23 mpg since I got it, driving a mixture of both city and highway. ---
**Author:** ![groman](https://avatars.discourse-cdn.com/v4/letter/g/73ab20/32.png) [@groman](https://boards.straightdope.com/u/groman)\ **Post date:** [January 31, 2007, 4:28am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/18 "2007-01-31T04:28:59Z")
[QUOTE=Johnny L.A.] '99 Jeep Cherokee. If I drive 65 to 70 mph I get 18 to 21 mpg on the freeway. If I drive 55 to 60 mph, I get 25 mpg. [/QUOTE] Point in case. For a period of my life I drove my parents '99 Jeep Cherokee that has an onboard MPG calculator (I also check MPG every tank out of habit). With almost identical highway to street ratio my MPG in the Jeep dropped to 15.5 from my stepfathers 22. Paradoxically I managed to get almost 17 when I switched it to full time four wheel drive and left it that way for several tankfulls. The difference is most likely not sustained speed, but rather how you accelerate – I’m gentle but when accelerating I typically keep my foot to the wall until I reach the desired speed. When my stepdad started driving the Jeep again his gas milleage went back to 22 mpg. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [January 31, 2007, 4:32am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/19 "2007-01-31T04:32:30Z")
Incidentally, a former coworker bought a Wrangler with a 4-cyl. engine because he thought it would get better mileage than the four litre six. What he didn’t think of though, was that on the freeway he was flogging the hell out of his four-banger while my (bigger, heavier) Cherokee was loafing along with its six. His mileage was much poorer than mine. ---
**Author:** ![Mr.Slant](https://avatars.discourse-cdn.com/v4/letter/m/c57346/32.png) [@Mr.Slant](https://boards.straightdope.com/u/Mr.Slant)\ **Post date:** [January 31, 2007, 4:57am UTC](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891/20 "2007-01-31T04:57:45Z")
Track this over at least 3 tankfuls of gas before worrying. Remember that in winter, the oxygenated fuel will likely sap about 10%, or 3 MPG, from most cars. I suggest buying a “Scangauge”. Plug it in, drive for at least 20 minutes, get onto a flat highway, set the cruise at 55 MPH, then reset the TRIP MPG gauge. Cruise for at least 10 miles, then note your mileage. Turn around, get up to 55 MPH, then reset the TRIP MPG. Run for 10 miles, then note the TRIP MPG. Average the TRIP MPG from both runs. If you don’t meet or beat your EPA HWY estimates, I guarantee you’ve got a serious problem. [Next page](https://boards.straightdope.com/t/why-is-my-new-to-me-car-getting-such-lousy-gas-mileage/389891.md?page=2)