So you need to replace you 02 sensors and you’re a bit lost. How often should I replace them? Where are they? Do I replace them all? What brand do I go with?

Oxygen sensors should be replaced every 60-90K miles. DO NOT wait until the engine light comes on. The Oxygen sensor ensures the correct air to fuel ratio. Having this ratio off, will cost you horsepower and gas mileage.

There is typically 2 sensors on vehicles before 1996. This is known as OBDC 1. There are 4 sensors on vehicles after 1996 and this is known as OBDC II. Usually half are located before the catalyst (catalytic converter) and half are located after. All of these are in the exhaust stystem just up from the muffler.

When you are the O2 Sensor, you should replace all 4 of them. Its just not worth getting in that far and not replacing all of them.

I usually recommend buying OEM brands, which is usually Denso or Bosch. There are a couple of good manufacturers of aftermarket ones, but there are some bad ones so be careful.