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Lexus IS 350/IS 250 Real World MPG Numbers



  • Anyone else with this problem? I got my 250 four days ago. It's now got 114 miles on it. The MPG calculator on the dash is showing that I'm getting an average of 13 MPG! Hello? Is that thing broken or what? i have done only city driving in LA so far, but seriously, my average speed is like 12mph. I think the MPG should be better than 13 MPG. Is it because the engine is new? Could this be because the the dealer did not use premium when they filled it up before i took delivery? i have not filled it up yet. Any thoughts would be appreciated!


  • samiam_68samiam_68 Posts: 775
    You need to go through a few tankfuls to get the correct MPG. What you're seeing is the result of the car idling a lot while still at the dealer.
  • carmonkeycarmonkey Posts: 32
    I recently ran 120 miles in my IS350 at an average speed of 110 mph and it got 16.32 mpg.

    To answer the inevitable question of where did I average 110 - check out
  • mrolliemrollie Posts: 1
    My 250 has 4000 miles and has averaged since new 27.0. The current tank (Hess 93) is giving 25.9.

    Not bad for a fun little car.
  • Just ran a full tank on the highway, about 340 miles no more than 10 miles in city conditions. Average speed 75 mpg (per the gauge). Fuel economy: 24mpg. THAT seems rather low. Any suggestions? Am using 91 oct. fuel and car has about 1950 miles on it. Got it in March...any thoughts would be appreciated... thanks

  • nicecarsnicecars Posts: 4
    My IS 250 has average of 22mpg. I have about 50% hwy, 50% local. It is below my expectation caz I used to have a toyota camry, which delivers average of 25mpg for 100,000 miles.
  • carmonkeycarmonkey Posts: 32
    You're still in break-in. Give the car another 2k-3k miles to see a jump in the mileage.
  • jzalkinjzalkin Posts: 56
    I am at 28mpg with 70-80% hwy. I have found that it drops if using cruise control and dips at and above 80 mph.
  • ar39ar39 Posts: 61
    I've observed Sunoco premium gives me a better mpg over other brands of gasoline, with 75% hwy 25% city driving in my 2006 IS250 AWD.

    Sunoco 91 - 28.4
    Exxon/Shell 93 - 27.7
    BP 93 - 26+

    Measurements were taken in similar driving conditions. Also, these are not dash monitor reading but, miles/distance calculation. The car monitor shows variance of +1.3 miles.
This discussion has been closed.