Unusually Poor Gas Mileage
- Thread starter SonicBoomhauer
- Start date
mitdr774
also a dinner prick
Do not go by the DIC for average. It is fairly inaccurate in most vehicles. Even over the past 61K miles mine is still a little optimistic. If you reset the DIC too often the "average" will fluctuate a lot over a tank.
Where do you live that carries 86, 88, and 90? Ever station I have gone to carries 87, 89, and 91 or 93. Last I was aware only a handfull of stations sold 86 and that was just to offer a cheaper alternative to the 87 that they also sold. I am not aware of any vehicle produced that recommends anything lower than 87.
I find the greatest contributing factors to poor economy are the result of how the driver is driving the vehicle.
Where do you live that carries 86, 88, and 90? Ever station I have gone to carries 87, 89, and 91 or 93. Last I was aware only a handfull of stations sold 86 and that was just to offer a cheaper alternative to the 87 that they also sold. I am not aware of any vehicle produced that recommends anything lower than 87.
I find the greatest contributing factors to poor economy are the result of how the driver is driving the vehicle.
XilliK
New member
I live in a crappy NM city and drive 15 min to El Paso, TX to get gas... I only use shell or chevron gas I reckon 87 unleaded wouldn't be good enough... doesn't seem to fluctuate much I like to stay around 40 and always use cruise control I just figured I'm breaking the engine in and therefore getting better mpg... guess I shouldn't expect anything better than 35 mpg then aye
shorebreeze
Member
I know I'd find it difficult to get 40 out of an RS, given the gearing. I have the 1.4 LT in an automatic, and when I was out on the highway this summer and early fall shortly after I bought the car, it was fairly straightforward to get 40 to 42 calculated. In city driving, 26 was more the norm if I mixed freeways and city streets, 23 if city streets only. With winter, with longer warmups and an inferior fuel formulation, it's more like 21 on city streets only. I'll update again when I next get it out on the highway. You need to realize that at 70mph, when an LT/LTZ turbo is pushing 2350rpm as an auto and 2150 as a manual, the RS in both versions is over 3000rpm (the gearing on the RS is fairly similar in both manual and auto). As a result, where the standard transmissions are EPA rated at 37 to 40mpg, the RS transmissions are EPA rated at 33-34. Competent and cautious 70-72mph summer highway driving will get you about a ten percent improvement on those numbers, but no more, and to crack 40 on an RS, now you're looking at steady-state 60mph or so driving, which is probably not why you bought the RS in the first place . . .
No doubt when the Cruze's 7-speed dual-clutch transmission comes out next year, intrepid members of this forum will be perusing it closely to see if it can fit in the Sonic and provide the RS with more sensible gearing.
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XilliK
New member
I think the semi-auto is enjoyable but I couldn't get used to the arm rest to save my life I usually try to hit 60 and cruise it because I'm staying in a rural area. If i reset the avg mpg while driving it easily climbs to 40 yet from a stop it's usually in the mid-high 30's. So really the only true way to see my mpg is do a mileage count from when a gallon is depleted? I rarely ever try to drive very fast unless I'm late for work... It's just a little bit disappointing especially since I paid 21k for it and the pull is just subpar
I've got a 2015 LT with the 1.4 liter turbo and the automatic transmission. As others have said in this thread; don't completely rely on the "AVG MPG" on the DIC as an accurate reading. I use an app on my iPhone called "Mileage Keeper" and what it does is allow you to add the date, odometer reading, fuel amount, cost of the fill up, price per gallon, and a couple other spots to add your own personal notes (I add where I bought the gas from and what octane I put in-although I only use 93 octane). So far, since I got the Sonic with 50 miles on it, and 4 fill ups later (5 including what the dealership put in it when I got the vehicle); I've only averaged around 27 MPG. I have about 1200 miles on it now and assume the engine isn't "broken in" yet so I guess I could contribute the seemingly low MPG to part of that. I live in south Florida and travel on I-95 to and from work about 4 days a week and my drive consists 54 miles round trip on those days. Other wise, if I'm doing anything on my days off, it's a short 14 mile round trip to the gym, twice. I'm not heavy on the gas pedal (unless I'm running late, haha) and try to feather the pedal as best I can and use the cruise as much as I can as well. I'm hoping my MPG will get better in due time, but time will tell. Either way, I was driving a 2012 Buick Regal GS (GOD I LOVED THAT CAR) and it had a 2.0 liter Turbo in it pushing 270 horsepower and it was QUICK......but could at best get 23-25 MPG when I babied the hell out of it! :-(
POINT BEING: I'd try and keep track of your MPG the good ole fashion way (or the more techie way via an app) and not rely on the DIC. The DIC in my car SAYS I average 30-31 MPG (and that's not resetting it at the beginning of each drive--not a good idea, let it average out otherwise you'll get crazy, unreliable readings with no true value or meaning), but when you do the real math, I'm only averaging ~27 MPG.
POINT BEING: I'd try and keep track of your MPG the good ole fashion way (or the more techie way via an app) and not rely on the DIC. The DIC in my car SAYS I average 30-31 MPG (and that's not resetting it at the beginning of each drive--not a good idea, let it average out otherwise you'll get crazy, unreliable readings with no true value or meaning), but when you do the real math, I'm only averaging ~27 MPG.
rwnoutlaw
New member
I live in south Florida and run 95 50 miles each way to work and avg 31-34 with city driving. I run Shell premium and drive between 68-72. Since you have the 1.4 you should do better on fuel than me. I tried racetrac 87 and 93 and only got about 28 mpg
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
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The Champ
New member
I can help you improve your Mile per Dollar spent by about 10% - just start using 87 octane purchased from a Top Tier fuel supplier.
I'm currently averaging over 35 MPG on 87 octane - locally that's about 10% less expensive.
Higher octane does not improve fuel efficiency and is not needed without tuning mods.
I'll try it out! Thanks.
VaBumbleBee
Member
HuH, WTF. Subpar? My Bumblebee gets 40 mpg and will bust most cars asses on the road.
Maybe you need a Prius .
So I tried what you've told me and haven't seen much of an improvement....if any at all. I've filled up with either Shell or COSTCO which are both Top Tier fuels as well, and purchased 87 octane each time. Going from 93 octane to 87, I noticed the engine seems to run rougher at idle (seems to drop idle and almost feels like sometimes the idle drops so far that it wants to stall out) and I notice all kinds of engine noises I never heard when I was running 93 octane. Not sure what to think about the MPG issue......but with almost 4,000 miles on it, it should be getting better than 26 MPG (my average after 4 fill ups since switching to 87 octane). I asked the dealership and of course they said to ONLY put 87 octane in it, so yeah. I'm beginning to wonder if the issue is something other than a fuel system issue. I have since needed the a/c compressor replaced in my Sonic (at 2500 miles) because I was getting some really loud noises and some drivability issues from it. They said the compressor was "coming apart" and when they took it apart they noticed metal shavings inside the system. I feel like I'm STILL having the same issues and I know that the a/c system can put a huge strain on the engine and it turn causes terrible fuel economy. Add that to a faulty system all together and it may be a recipe for headaches!
Oh yeah, the dealership also told me when I asked why I'm getting such terrible fuel economy, that it takes 5,000-10,000 miles for the transmission to "learn" and until then I'll continue to experience low MPG's. The transmission in my car definitely doesn't feel like a normal transmission should when downshifting either. It almost feels like it throws me forward (the effect you get when you are traveling at a high speed in a low gear in a manual transmission, then let off the gas....if that helps explain it) and it also seems like it wants stay in a lower gear when I'm traveling at slow speeds around 5-10 mph. The engine seems to be winding out at a much higher RPM than it should be.
Love the car but DAMN, it's been tough to figure out! I miss my 2012 Buick Regal GS!! Was a 6 speed and FAST and had TONS of power and the turbo sounded like a semi when I hit the gas!! Haha! The payment was the downfall......as well as the MPG. I was getting the same MPG in that car as I'm getting in my Sonic....and the Sonic has 130 LESS horsepower :-( :-(
2014 Blue RS
Active member
I average 28mpg on highway at 80mph. 36 if I keep it under 70mph.
Around town 19
Around town 19
The Champ
New member
I said I could save you about 10% on your cost per mile. And based on your results, I underestimated your savings.
You're still getting the same MPG, but you're paying about $.55 per gallon less for your fuel. I don't know what part of South Florida you're in - but 87 octane is about $2.15 per gallon in Miami right now and premium runs about $2.70 per gallon.
So you're saving about 20% on your cost per mile by using 87 octane.
I can't explain why your mileage is so much different than mine. I just drove to Madison, WI this past weekend. On the way down I drove on mostly 2 lane roads at speeds of 60 - 65 MPH and got 37 MPG. On the way home I took the interstate and drove 73 MPH and got a little over 35 MPG.
My Sonic just turned 11,000 miles over the weekend. But even when brand new I've never gone below 30 MPG - even with mostly in town driving.
RMinNJ
Active member
Ditto.. I think cold and winter gas plus for me new tires has dropped my overall mileage. Stinks. But the car runs great.
For the problem above I say maybe get yourself an ultraguage and start comparing various numbers to others here? Not really fair for the dealers to blow us off and discount any Mpg problems. Maybe go for a ride with the mechanic ...0 the mpg.
Then pick a new sonic off the lot and do the same drive..note the mpg.. if yours is 26 and the other sonic 37 tell then to fix yours.
For the problem above I say maybe get yourself an ultraguage and start comparing various numbers to others here? Not really fair for the dealers to blow us off and discount any Mpg problems. Maybe go for a ride with the mechanic ...0 the mpg.
Then pick a new sonic off the lot and do the same drive..note the mpg.. if yours is 26 and the other sonic 37 tell then to fix yours.