No check engine light only mods are header, exhaust, and cia. The car has 130 miles and gas mileage stared to take a crap out of nowhere. I will check the o2 sensor today if its the o2 sensor any suggestions on a good replacement one.
what could cause my car to run rich. I already checked spark plugs and they were black i changed them out and the car is still running rich what else should i do next. I have researched already just want to know what you guys think