Hello!

My C Ex 2000 (auto), has about 173,300 miles on it, and gives me about 20/mpg in town and 25/mpg on highway.

I think it is eating a bit more than it should.

What do you think guys?

If you agree, any suggestion will be greatly welcomed.

 

That's a bit low.

Have you done all the routine maintenance stuff, like spark plugs, wires, injector cleaner?
Have you had the compression checked?
Are your tires properly inflated?
Do you have a check engine light?
Does the check engine light work? (Does it come on when your first start the car, then turn back off?)
Are you carrying any extra weight in the car? Stuff in the trunk or back seat, for instance?
Do you have aftermarket rims?

 

Have you done all the routine maintenance stuff, like spark plugs, wires, injector cleaner?

Answer:
I did change the spark plugs almost a year ago. The wires are original. I do know anything about injector cleaner.

Have you had the compression checked?
Answer:
I have not. I probably need to do that. The car starts right up, this is why probably i never had that checked.

Are your tires properly inflated?

Answer:
Yes. I just did check them.

Do you have a check engine light?

Answer:
No, I don't.

Does the check engine light work? (Does it come on when your first start the car, then turn back off?)

Answer:

Yes, it does work.

Are you carrying any extra weight in the car? Stuff in the trunk or back seat, for instance?
Answer:
No. I don't.

Do you have aftermarket rims?

Answer:
No, I do not have aftermarket rims. I have the original ones.

Thank you, for your assistance. What do you think it could be done, with this much you know now.

 

changing the air filter may help a bit, as will changing the pcv valve. changing the air filter is real easy, but the pcv valve can be hard to get to. How did you come up with the 20/25 numbers? Do you have an scangauge, or are you estimating? Driving style and whether or not you are driving up and down a lot of hills may also be a factor, but probably not enough to account for how low you mileage is.

I'm confused about whether you have a CX or an EX. If you have a CX, you could check your exhaust manifold to see if it has a crack where the top oxygen sensor is. It could be that the crack isn't bad enough to set off a CEL but is still affecting your mileage.

 

@imadvanced, "C EX" = civic EX.

Wolf83, I would recommend replacing your spark plug wires. If they are original, or even if they've only been replaced once, it's a good troubleshooting step and it's really easy to do. Those wires wear out over time and if yours are old, they can lead to problems like this. Hit up your local Autozone or Advance and pick up a set. Worst case, you just did some routine maintenance.

While you are there, pick up a bottle of Lucas fuel injector cleaner. It's like $4 a bottle.

I would change your plug wires and then fill up on gas, then wait until it's time to fill up again. See how your MPG is. If it's still low, put the bottle of Lucas in the mostly empty gas tank and then fill the tank to full. Drive for another while and check your MPG.

If it's still low after that, go back to Advance or Auto Zone and grab a can of this stuff called "Restore". It's in a little silver can. Shake it well, then pour it in with your oil and drive for about 200 miles or so. See how your fuel economy is. If this adds MPG where other things didn't, it's likely that your piston rings are worn. You can put a can of Restore in with your oil at every oil change.

I recommend these in order so you can see if any one of these makes a difference instead of doing them all at once and not knowing which helped.

 

Honda Civic ex 200 mpg
Cost to Drive 25 Miles $3.31
Fuel to Drive 25 Miles 0.93 gal
Cost to Fill the Tank -
Miles on a Tank -
Tank Size -
Annual Fuel Cost* $1981

Saving the fuel cost. Very nice car.