The oxygen sensor helps control the fuel air mixture to the engine so that it runs properly. If it's responding too slow, meaning the computer isn't recieving a signal from it when it should be, your engine isn't running right. Possibly running richer than it should be for a longer period of time. Noticed any decrease in performance or more importantly, fuel milage?
As for the location, if I'm not mistaken, I believe the KJ has two. One is on the exhaust pipe, right behind the right front tire. Go out and turn the wheel all the way to the left, then go to your right tire and look at the part of the exhaust pipe you can see. You'll see what appears to be a spark plug looking thingy coming out with a wire running up towards the engine. That is an o2 sensor. Thats atleast one that I know of, and like i said, I believe there is another one. Could be mistaken on that. I'll go out and look later when it cools off.
