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Thread: SO my lofty fuel economy goals are obviously out the window.

  1. #21
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    I got one last week, used @ 43k miles. I too was getting mid 30 mpg no matter what. After adding marvel mystery oil in the gas and oil (and changing oil) I didn't see an improvement. But I slowly pushed the gas pedal to the floor a couple times and kept it like that til I was doing 80+ from 40mph. Now it's much better. I assume it was driven very nice and never went into higher rpm's. Stuff will gum up over time and if you don't get rpm's high it will never get the sludge off. Of course you will probably need a system cleaner of some sort in the system. I thought there was something wrong but I think it was just never opened up on the highway.

    FWIW, the "normal operating temperatures" given to cars is there for a reason. At ambient temps, the pistons are slightly smaller, then when the car is warmed, the pistons swell ever so slightly, thus meeting the intended tolerances for the engine. Until it's warmed up the piston has very slight lateral movement at a microscopic level. This is why engines experience the most wear at startup, a piston will "rattle" in the cylinder vs sliding. It's best to warm it up, and as the manual states, when the green temp icon disappears, it's warmed to operating temperature.
    Physics and all..



  2. #22
    Member iriegnome's Avatar
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    I feel you on this one. My avg mpg was about 47mpg in the fall. I bought my 2018 in October. I drive 100 miles per day. Great mileage. Then it got cold. My average is down to 41.6 mpg. And my daily goes as low as 35 mpg because I have to run the heater enough to keep the windows from fogging up.. BTW, this is not a great car for defrosting country here in the upper mid-west! Also, I started getting worse gas mileage after I took my car to the dealership for my first (and free) oil change.

  3. #23
    Have you checked your oil level to see if they over filled it? They like to do that sometimes. Or maybe threw in 5w20 or 5w30? I'd hope you're dealer is brighter than that but I know the dealer closest to me isn't.

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        click to view fuel log View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)


  4. #24
    Administrator Daox's Avatar
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    Quote Originally Posted by iriegnome View Post
    ...I have to run the heater enough to keep the windows from fogging up.. BTW, this is not a great car for defrosting country here in the upper mid-west!
    A grill block totally fixes that IMO.
    Custom Mirage products: Cruise control kit, Glove box light, MAF sensor housing, Rear sway bar, Upper grill block

    Current project: DIY Nitrous oxide setup for ~$100

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage DE 1.2 manual: 47.2 mpg (US) ... 20.1 km/L ... 5.0 L/100 km ... 56.7 mpg (Imp)


  5. #25
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    Quote Originally Posted by iriegnome View Post
    I feel you on this one. My avg mpg was about 47mpg in the fall. I bought my 2018 in October. I drive 100 miles per day. Great mileage. Then it got cold. My average is down to 41.6 mpg. And my daily goes as low as 35 mpg because I have to run the heater enough to keep the windows from fogging up.. BTW, this is not a great car for defrosting country here in the upper mid-west! Also, I started getting worse gas mileage after I took my car to the dealership for my first (and free) oil change.
    I see about a 5 mpg difference between summer & winter. I would say my numbers are about 47 summer & 42 winter, too. February was exceptionally cold this year. Had some tank fill ups around 40 then. Adding an engine block heater helps the inside of the car warm up better, too.



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