General engine questions/issues that aren't specific to the other categories
By jerryhaddensworth
#64787 got a 93 dx hatch with 206k miles, 5spd tranny, bone stock motor, and im only getting 25 mpg city. I just changed the oil and air filter, but ran the tank dry (full 11.9 gal) and only got 300 miles out of it...im no math major but thats only 25mpg. I baby the hell out of this thing to try and squeeze every penny out of the gas tank. Whats wrong......that seems pretty weak for this car, thought they were supposed to be in the 30mpg range for city and like 34 for hwy?

Any info?
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By hannibalhekki
#64793 check the sparkies, spark wires, fuel filter. i recommend a seafoam cleaning, but be careful cuz some people get different reactions to it. :?
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By Classiccarsrule85
#64799 besides checking all that stuff he posted up top of me....I would also see about taking that valve cover off and looking at the wear under it though you wont see alot of difference you might have something that is just not allowing your car to get that kind of mileage most cars start losing power and fuel mileage by 175k so your motor might just be getting tired....
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By suspendedHatch
#64847 First of all you need to learn how to calculate mpg. You don't run the tank dry and then divide it by the tank size. This is nowhere near accurate or repeatable. What you do is fill the tank using the pump's auto click. Reset your trip meter. Drive a couple hundred miles. Fill the tank again, preferably at the same pump. How many gallons you put in is also how many gallons you have used. Divide this and the miles indicated by the trip meter.

Tire pressure, air filter, ignition timing, O2 sensor.
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By biretsu89
#64856 ... I am driving a vx civic... and the fuel gauge goes on E when I only have driven 235 miles.... I am pretty sure that the tire size is not correct for the alloy wheels it has... And I am sure my O2 sensor is jacked due to my motor shitting out black exhaust....
By BADD EGG
#64872 Just do a major tune up.

Plugs (gapped correctly)
Wires
Cap and rotor
Fuel filter
Air Filter


seafoaming is not a bad idea either. Just follow the directions on the can. I know a few people that have had great results with it.

Your motor may just be tired from a long life. Hopefully this isnt the case. Hope your tune up goes well. It can all be done in a driveway which is another good thing.
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By k0rean4life
#65433 Check ur timing, Over here at INLINEFOUR we get a lot of cars with this problem 80% of the time its the Timing. Than afterward I would inspect ur spark and wires and cap and rotor. IF not bad O2's can do this
By sqsi
#65525 Any update on this? It is odd since I have an Si with 205K getting 33 MPG and I don't baby it at all.