I have a 98 Jimmy with 100,000km on it. I've never replaced an O2 sensor
on the vehicle, and according to a scantool the output of the O2 sensor(s)
is cycling on & off (which is normal).
Should I replace them anyways due to age? (The gas consumption is high on
this vehicle - higher than 3 years ago).
And the tough question...where are they located?