I own two Nissans...a '95 200SX SE-R and a '97 Maxima SE. Let me start with the 200SX: the car was recently showing KS and OS codes. So...I replaced both O2 sensors as well as the KS. The result? No difference whatsoever (the codes went away though!). The car ran 95% perfect b4 I replaced the three sensors and it runs 95% perfect right now (very slight blip every now and then through the rev range). I'm showing the same two codes on my Max right now. The car idles perfect, gets 24/29 mpg and has gobs of power with absolutely no hesitation. My question is: WTF is up with the codes? A person could spend hundreds and hundreds of dollars replacing sensor after sensor and wind up with the exact same car at the end. Are the various sensors simply hypersensitive or ??? Just looking for some clarification...thanks.

 

Sometimes you may have a code that is tripped by something else. In which case knowing that and replacing just one sensor or part could save time and money. Some have had the KS code but didnt get the bad gas milage and/or bad acceleration, but the KS is still faulty and needs changing.

If your 200sx still feels sluggish but codes are gone, then check else where. You can have a dirty air filter and have a sluggish car, close to the same with tire pressure. There is a lot to factor to check out.

 

An o2 sensor code usually triggers the KS code as a ghost code. Just because you get a code for an o2 doesn't necessarally mean it's completely shot, it means the signal from it has gone out of the acceptable range.

Replace the o2 and clear the error codes, then check to see if the KS came back. If so, replace it as well.