By June 17, 2008 Read More →

Gas Mileage Not Good Any More

Hi, my Honda is only getting between 200-300 km per tank. A few years back it was going near 700 km. I had $600 worth of service done a few months ago. I change the oil every 3 months. Air filter has been changed. New spark plugs.

The car is running excellent but it did not improve fuel efficiency. It passed air care easily. I showed the air care report to a mechanic and he said there was nothing else he could do to help. Any ideas what could be wrong?

Thank you for your help.

Hello there,

If the engine is truly running properly, as the air check report SHOULD indicate. I would spend a little time investigating the following

  1. Are you using the correct WEIGHT of engine oil? Probably 10W-30 should be used anything else would be too heavy and decrease mileage.
  2. Double check your tire pressures. Under inflation is probably the biggest cause of poor fuel mileage.
  3. Check the spark plug “gap”. Are the proper spark plugs installed, and is the gap between the electrode set correctly
  4. Are the spark plug wires worn out and due for a change?
  5. Does the car run ok? Did you have the timing belt replaced……then immediately after that you noticed this decrease in economy? If so, the timing belt could have been installed incorrectly just enough to affect the performance of the engine but not enough to show up on the air check numbers.
  6. Try a different brand of gasoline, some brands put additives in the fuel that can adversely affect fuel mileage.


Austin Davis

About the Author:

Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."

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