I just but a catback exhaust kit and headers on it. And im using another o2 sensor cause I couldnt get my other off my old manifold. Aldso I nltice all my header pipes change color except for cylinder one . What does this mean ?

 

What kind of header? Painted? stainless?

 

stainless i belive i have a faulty o2 sensor. but i also think cylinder one might have a bad valve or something because it dosent get as hot as it should like the rest of the cylinders