Jared Everett
New member
i went from almost 500 miles a tank to less then 250 a tank. my car is mostly stock but i do have new headers and exhaust system and an intake my headers and exhaust r off a 99 civic dx hatch so the exhaust is short and my oxygen sensors r in different places but i ran new o2 sensors and for a month or 2 my mpg didn't change could the new headers since my o2 sensor is reading off only one pipe instead of all 4 be my issue or is it something else and if so what else could it be? i replaced my rotor button distributor cap and put in performance wires and spark plugs. i have also replaced my fuel filter. my check engine light is on but it does’t say anything about my air flow sensor i believe it says something about my oxygen sensor bank one. my check engine light came on shortly after i installed my headers and exhaust system i had my intake for a month or so already.