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samhain7's avatar
samhain7
Explorer
Apr 05, 2018

Gas Mileage on 2014 Dodge Ram 2500

Hi all.
My truck is a 2014 6.4l Ram 2500.
Lately, I have been getting worse and worse gas mileage and just wondering if anyone had any suggestions. (Yes, i will book an appt with the dealership but would like to know things they should check and questions I should ask).
I also know the facts I am giving you are the lie-o-meter, but it should be constantly lying...
So I used to get around 18l/100k. I do about 60% of my driving on the highway.
Witin about the last 6 months, I struggle (with conservative driving) to keep it under 22l/100km (around 11mpg). I am not towing anything and I have nothing in the bed.
I have tried replacing the air filter which helped a tiny bit, but I am just confused why I would suddenly start getting this difference in mileage.
Thanks and take it easy on me! ;)

5 Replies

  • Winter gas is a pain. I recently had some serious mileage dropoff. Switched to a better grade of gasoline, 87 to 89 octane, and all was better with the world. In fact, I ran a tank of non-ethanol gas through it first, which made an immediate difference in performance. Mine is the 1500 with the 5.7 though.
  • That seems excessive for sure. My old ‘14 5.7l would average about 15l/100km mixed driving. Towing my 8k tt I would see around 25l/100. There is sometimes a noticeable difference with winter grade fuels but not that bad.

    Are you hand calculating or from the EVIC? Do you rest it after fillups? Do you use a remote start and idle a lot?
  • My 2012 Ram 5.7 started to lose gas mileage. Along with replacing the air filter I took off the throttle body and cleaned it and the MAP sensor. Mileage came right back.
  • First off........

    Hand calculate 2 tank fulls to get a better idea of what your mileage is VS that Lie-O-Meter

    Lie-O-Meter may just be getting worst and not the 'real' mileage

    Then it's a matter of hooking truck up to diagnostic and check all functions
  • Guesses...


    • Seasonal change in fuel mixture (additional of alcohol to the blend) that will take the computer time to re-learn HOW2 meter
    • Tire PSI getting low
    • Intake system and exhaust system...sensors might need cleaning (careful, follow directions from your manual and bottle of cleaner...some will ruin the sensor)...plugging up exhaust system...mainly the CATs...more so if you have used additives NOT good for the CATs...intake air filter needs change
    • Basic tune up needed...plugs, even the expensive platinum wear out


    Suggest checking/flushing all fluids, as they may have gone past their useful life

    Bearings...sometimes they start going slowly...creating drag

    Be sure to have them explain any codes that comes up and note them on the work-order.

    Good luck !