i just got my nismo header installed and after one day of having it my check engine light came on. i got worried. i got the nismo intake and exhaust as well and got everything installed by the dealership. well the next morning i took the car to the dealership and they said that the light came on because of my header that didn't have a cat. they said that there was this sensor i can buy that would eliminate this problem. please help i dont have one idea about this. i just get tried of seeing the check engine light on. It makes me feel like there's a problem with my car even though theres not.