I have a 1997 honda civic ex 4 dr @ 158kmiles and i am currently getting 24MPG. I drive it like i should i shift a 3000-3500rpm everytime which is normal. I have done everything i can to it to improve gas mileage. I have done plugs, cap, rotor, air filter, oil, oil filter, fuel filter, pcv valve etc... My girlfriend drives a 2001 honda civic lx 2dr and she drives the **** out of that car.. She takes it to 6000rpm every shift and it seems like shes getting 45+mpg city. When my car is at half a tank im at 100miles.. Today hers said it was at a full tank and her trip said 100miles too.. Something is wrong a half tank for me is still a full tank for her WTF?!?!?! I seriously need some help here. I cannot think of anything else i can do to my car. I have added headers, muffler, and rims and tires. Tomorrow im going to put on another stock manifold and see if that helps at all. If that doesnt help then im going to do the muffler and if that still doesnt help then im going back to the stock wheels. But i cant see doing those 3 things making much of a difference in my mileage. Can anyone help me?

 

What size are the wheels? How much do they weigh? Is the tire pressure correct? Have you had a recent alignment? Valve adjustment? What type of driving do you do city/highway/combo? 24 isnt all that bad, but it should be better. My 98 EX gets 30 mixed and about 37highway. 25 city.

 

header, muffler, and no cel, no exhaust leak, even a tiny one from those headers???

 

I have 16 inch wheels on mine and it brought my mpg down a little.

I also have cat back mid pipe, and muffler and now headers, overall I get around 25.6

96 Civic EX auto.