check engine light on on 2000 Mercury Villager

was told the problem is o2 & nock sensors, the car runs fine but will not pass inspection. it has 135k miles. how much to repair?

Asked by for the 2000 Mercury Villager
resolve the o2 problem and the knock sensor code will not return. nissan had issues with the 325 code appearing with every other code when in fact there is no failure of the knock sensor.

cost Hello?