Where is the third o2 sensor located, and is it a bitch to get out? My dad just called me and said that his check engine light came on. He took it to a parts store where they did a diagnostic check. It said the third o2 sensor was bad. I haven't confirmed this yet, nor have I looked under the truck to find it. I will see him in the morning before work and planned on changing it out for him. I know o2 sensors aren't that hard to change, but I was just wondering if anyone can give me a heads up on where it is exactly. I'm thinking it's behind the cat. I have the correct socket already.
