i bought a 97 civic ex in august and i have noticed i am only getting around 220 miles on a tank, i think that is way to low for my car, i have added a muffler, cold air intake, rotor/wires/dis cap/spark plugs, and my speed sensor is bad so i have ordered a new one (check engine light came on and code was for speed sensor), but idk i dont have any extra stuff in my car stock stereo and stuff, o ya i got new tires and brakes and i also replaced my axles, so what might be the problem to my bad gas milage i dont push my car that much i drive around 65-75 on free way and speed limit on city so is their anything i can do to gain milage?

Thank You
-Andi

 

Maybe a bad oxygen sensor? My 98 EX gets about 34 mpg overall per tankful, and that's with a bad oxygen sensor that won't let the car go into closed loop mode. Check to see if your brakes are dragging and for a fuel leak also

 

I could see how a def speed sensor would provide false data (MPH) to the comp in a closed loop condition, forcing your injectors to provide more fuel then whats necessary. 220 mi's is in the dirt. Be sure to reset your computer by disconnecting the the battery for about 30 min, don't forget the security code for the radio. it will force your computer to re-learn, otherwise it will be driving with bad historical data and will take longer to see the improved mileage.