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Improving gas mileage?

Discussion in 'General Jeep Discussion' started by Tenchu056, Oct 21, 2019.

  1. Oct 21, 2019 at 1:53 PM
    #1
    Tenchu056

    Tenchu056 [OP] Member

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    I have a 2007 jeep grand Cherokee limited with the 4.7L V8 and I don't want to get rid of it but it getting horrible gas mileage, 12 mile to a gallon. What can I do to improve the gas mileage?
     
  2. Oct 21, 2019 at 1:55 PM
    #2
    Prerunner1982

    Prerunner1982 Well-Known Member

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    When was the last time some preventative maintenance was done?
    That vehicle is only rated at 15 mpg city and 20 highway.
     
    TinyInkognegroT likes this.
  3. Oct 21, 2019 at 2:01 PM
    #3
    Prerunner1982

    Prerunner1982 Well-Known Member

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    Also Brian, welcome from Oklahoma.
     
  4. Oct 21, 2019 at 2:05 PM
    #4
    Tenchu056

    Tenchu056 [OP] Member

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    Even after the preventive maintance is done it still doesn't get the gas mileagfe it should, is there any after market modification I can do to improve the mileage?
     
  5. Oct 21, 2019 at 2:11 PM
    #5
    Prerunner1982

    Prerunner1982 Well-Known Member

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    Is the vehicle modified?
     
  6. Oct 21, 2019 at 2:16 PM
    #6
    Awrench

    Awrench Well-Known Member

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    funny you ask about aftermarket my question is - Is the jeep STOCK - exactly as it was delivered?
    No aftermarket modifications, parts, additions?

    Do you have a scanner to look at live data?

    But realize you purchased a 2 1/2 ton SUV with a V8 and 4WD, not exactly prius thinking in design.

    But lets take a look at what is going on here.
     
  7. Oct 21, 2019 at 3:04 PM
    #7
    Tenchu056

    Tenchu056 [OP] Member

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    yeah it is completely stock I got from my parents.
     
  8. Oct 21, 2019 at 3:13 PM
    #8
    aggrex

    aggrex Well-Known Member

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    JGC with V8 is a hoot to drive but 12 mpg is on the low side. But is that city mpg or average mpg? The 4.7 V8 in good tune should probably average 15-17 mpg no matter the EPA rating. YMMV and is influenced on your commute and how the JGC is driven.
     
  9. Oct 21, 2019 at 3:25 PM
    #9
    Tenchu056

    Tenchu056 [OP] Member

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    It is fun to drive and I want to make it into a project jeep but to start I want to get better gas mileage and then work from there.
     
  10. Oct 21, 2019 at 3:49 PM
    #10
    aggrex

    aggrex Well-Known Member

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    Just to keep things in perspective in stock form the typical JKU averages 15-17mpg. But we should expect those mpg numbers to tumble down when bigger heavier aggressive tires are used, armor and heavier bumpers are added and lets not forget regearing. Your project Jeep is not likely to do much better. Trading in for the JGC V6 will only bump the mpg numbers between 2-3 more so enjoy the ride!
     
  11. Oct 21, 2019 at 3:52 PM
    #11
    Tenchu056

    Tenchu056 [OP] Member

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    Ok. I have another question about lifts, I been looking at lift kits but it only seems that they make them to lift the jeep only 3.5 inches, is there any brand that does a 5.5 lift for that type of jeep?
     
  12. Oct 21, 2019 at 4:35 PM
    #12
    Jim Beam

    Jim Beam Well-Known Member

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    I had an '07 Grand once and did get the 15-17mpg with the 4.7. I had to get rid of it as it developed an intermittent ignition miss that not even the pros could fix. I also had a '96 Grand that I had to get rid of because I had too much fun with it and it showed. It would have cost me too much to fix it but I'm sorry I let it go.
     
  13. Oct 22, 2019 at 2:33 AM
    #13
    Awrench

    Awrench Well-Known Member

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    x2 Do you have a scanner to look at live data?
     
  14. Oct 22, 2019 at 6:07 AM
    #14
    Prerunner1982

    Prerunner1982 Well-Known Member

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    Generally you won't recoup the cost of aftermarket products in fuel savings.
    One of the first things that come to mind as far as a reason for the low mpg could be the Oxygen sensor.
    Also is the engine getting up to temp? If the engine is staying too cool it may dump more fuel into the engine to try and get the engine up to temp.
     
  15. Oct 22, 2019 at 8:58 AM
    #15
    Awrench

    Awrench Well-Known Member

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    Alex I will take diagnostics for 500$ -
    It is used to look at ECT, o2 sensor and other engine readings ?

    PS A 5+ inch lift for a WK? Ringling Brothers or Barnum Bailey Have experience.
     
    Last edited: Oct 22, 2019
    aggrex likes this.
  16. Oct 22, 2019 at 9:23 AM
    #16
    Prerunner1982

    Prerunner1982 Well-Known Member

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    Due to the IFS style front suspension larger lifts just aren't all that great and provide little increase in suspension travel and can cause alignment/steering/wear issues. Superlift does make a 4" but that is about the largest I see.
    Is the lift just for looks or what type of off roading are you wanting to do with it?
     
  17. Oct 22, 2019 at 9:39 AM
    #17
    aggrex

    aggrex Well-Known Member

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    Big lifts done right will look good but maintaining the 12mpg with the JGC could be a challenge.
     
  18. Oct 22, 2019 at 4:32 PM
    #18
    Tenchu056

    Tenchu056 [OP] Member

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    I will be using the jeep for mudding and trails.
     
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