before you start make sure what bank it is. If it is bank one then it is near the firewall. There are similar post on how-to's here . I'll let you in so you dont have to search. Bank on is the one by the firewall. First take the coil pack off and you can see with a flashlight where the sensors sits. Follow the cord and you ll see that left to where the coil pack is there is a plug. This is the connection, you can go ahead and take it of before or after. Next You'll need an O2 sensor socket. Go to autozone where you can get your code checked for free, they loan tools out with a slight deposit. I beleive that this was about 20.00 buck or so. Just take it back and you will get your money back if not striped. This is the tricky part. You will have to use jack stands to have the car lifted, if not you wont be able to guide the sensor in and will take forever. Put the socket in in the sensor by itself from underneath the car it will be easier trust me I tried both ways. Then take a rachet in with someone helping you fromn underneath the car to guide the ratchet in the socket hole and the socket into the sensor while you are over the hood the person underneath will guide it. Once it is in this is the hard part, (I used a bit of wd40 to loosen up the stiffness in the threads) once it has been guided in you will need some sort of leverage on the wrench to loosen it. What I did was use the lever from the jack. Once you have enough leverage you want to pull up on the bar towards the hood. It will take a few tries but trust me it will loosen. Once you have that loose you will be able to unscrew it with your hand. Once you have the out you know what to do from there everything is downhill from here. Don't panic once the car is started doing your intial test when you see smoke coming out underneath the engine that is just the manifold heating up and burning up the wd40, that will go away quickly. If you have any ?'s let me know ....Oh yeah and dont forget this is for Bank 1. Now just wait to see if your light comes on again a day or two afterwards mine did it was I believe bank 2 the one on the catylic this one is easy. You will see once your underneath the car it is within hands reach ....good luck!