[89champ]

I have a 2016 civic lx 2.0. I drive 120 miles daily . 98 percent highway. No stops 65 mph cruise on the whole way. Fuel mileage was always 43-44 mpg after break in. Getting 38-39 now. It does have a 150 thousand miles on it. New air filter, always keep oil changed when needed. Is this decline in mileage normal for the miles on the vehicle or could it be something else. Curious if anyone has ideas or seen this happen on their civic.

 

[schen0228]

Spark plugs might getting worn out. Try to swap in some fresh ones.

 

[JudgeCrater]

I have a similar problem. I lost 4-6 mpg when I changed the original Continental tires for a much better handling tire. The original OEM were optimized for mileage.

 

[SARDAUKAR]

I have a similar problem. I lost 4-6 mpg when I changed the original Continental tires for a much better handling tire. The original OEM were optimized for mileage.

Same thing just happened to me with new rims and wider, Z rated tires.

 

[hannarase]

There can be two reasons why you have such a high fuel consumption. Most people have higher fuel consumption than they need because they have an aggressive way of driving. You can search on cararac.com for what consumption you should have while using different ways of driving. If there is something wrong, it can mean that something is wrong with your car. I can suggest you go to a car repair shop. Usually, it means a crack in the fuel system, and you a losing fuel while driving. This can cause a lot of problems in the future.