I did another gas mileage check. This time I refilled after 238.9 miles. It was mostly suburban driving, not much highway.
27.6 mpg.
This is an all time low. Usually, with my all local driving I get around 28.5 mpg. What is this with this 30 mpg - City that Honda claims? I don't think you can get it. I have a friend who has a Mercury Grand Marquis and he gets 26 mpg highway. That's a great thought, 26 with a Grand Marquis and 27 with a Civic.
Use Premium gas, then add some NOS brand racing fuel octane booster. Now your octane will be around 98 to 100. I think the addition of this additive makes the engine run hotter which will probably burn of deposits at the fuel injector. I tried this myself but only once. Not sure if it safe to use the octane booster on our cars. Well the result was better gas milage. I tried not to accelerate quickly so I can see the results after a whole tank. I noticed that my overall milage after the whole tank was 330 miles. Before doing this I always use regular(89 octane rating) and my total milage for a full tank was always under 300. The highest I got after 6k miles was around 280 miles. When I first got the car it was like 400 miles after a full tank! I don't know what happened to the fuel effiency with my car. Well I hope this helps. Later.
Roughly 38mpg on 87 octane here. I use Chevron Techron fuel system cleaner every other oil change.
Octane boosters really don't raise octane much at all. When the bottle says it raises octane by 3 points, it's really a .3 octane gain. Think about it...say your 10 gallon tank has 9 gallons of 94 octane pump gas in it. Then you add 1 gallon of 120 octane race fuel. Your total octane is now only 96.6 octane. That's a 2.6 octane gain. A little tiny bottle of octane booster that claims 3 point increase doesn't do jack. The big question is, why raise your octane level at all? Our cars are tuned for 86 octane, and can't benefit from higher octane as they have no knock sensors to advance/retard the timing.
If your getting poor fuel economy, try a different gas station. Amoco would be my favorite.
It sounds like everyone thinks I got one of the Civic lemons. What is it about a one out of five chance of getting a lemon Civic? Why would some get 27 mpg and others 35 or 38 mpg?
Hey I am having the same problem. I was driving on the highway and I usually can go around 200 miles on half a tank. Well, I hit 7K miles and now I am gettin maybe 115 on half a tank. I do mostly highway driving so I don't know what happened. I put a fuel injector cleaner in and it helped a little. But just wanted to let you know your not the only one with the problem. If this continues on much longer I will be taking it to the dealship.
~Leah
Well, I also have the HX coupe. It's gear much differently than the others. 80mph in 5th gear is only 3100rpms. How many rpms is 80mph on an EX?
Also, if you're trying to improve your fuel economy with a fuel system treatment try the Chevron Techron. It's the only one that's really worked for me. You'll know your fuel treatment is working if your mileage goes to shit when it's in the tank. After a couple of fill-ups mileage should return higher than what it was originally.
Humm thats an idea, I probably need to do that never have I have like 10 K or so on my ride now. On my 88 I noticed a lot better gas mileage after the treatment.
I've tired different gas, and different gas stations. I get generallly the same, averaging about 26 City, and 33, my last road trip. I must have one of those lemon Civic's too. I have to make an appt for an oil change and have the dealer look at it. I bought the car for the gas mileage, and it really isnt that great, good yes compared to my last car. Oh btw, my car is completely stock.
