EDIT - mileage largely improved! Details here.

Howdy fellow Opponauts.

My used car gets pretty poor fuel economy and I’m soliciting collective Oppo-wisdom for suggestions on improving this.


It’s a 2006 Hyundai Elantra GT (the XD2 variant - 2.0L Beta II engine, CVVT) with a bit under 100,000 miles on the odometer. I’m at least the second owner so I don’t have a history on it.

First: it’s not “the loose nut behind the wheel.” I drive like my grandmother - smooth, slow acceleration, thinking a mile ahead to avoid having to use brakes as much as possible.
Yes, it’s an automatic and I’ve been doing a fair chunk of city driving.

Drivers on Fuelly report a median near 30mpg; I’m averaging 22mpg. (I don’t rely on the trip computer’s mileage readout; I log my fill-ups.)

  • I’ve had the plugs and ignition wires replaced.
  • I’ve had the heater-core and coolant flushed, thermostat replaced.
  • downstream (rear) O2 sensor has been replaced.
  • Smooth most of the time, occasional rough idle but no stalling.


Valve clearance (lash?) is mentioned in the maintenance schedule but the local dealers don’t really seem to know much about that.


Things I’m thinking about:

  • Have fuel injectors ultrasonically cleaned. (dealership suggested this as a next step but they don’t have the facilities to do it)
  • Fuel filter?
  • Air filter? (doesn’t seem dirty)
  • Transmission flush?
  • More precise wheel alignment? (tires are correctly inflated)
  • Possible partial brake seizure/rubbing?
  • Bad wheel bearing?
  • CV joint worn?
  • Wait for warmer weather?
  • “Suck it up it isn’t a hybrid?”

Photos for either enjoyment or pity:


Stock photo but it’s nearly this clean:

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