Is there anything i need to do before or after changing the 02sensor? Also any tips on how to go about changing it? Thanks!

 

use the O2 sensor socket that looks like a deep drive, not the offset one.

run the car to warm up the exhaust pipe, it will come out easier, though it's a pain to work on (mine was really seized up)

i actually took it to a shop, and paid $44 including the $27 sensor. work out a deal with a mechanic, it's much simpler, and once you buy a $27 sensor and a $7 socket with the cutaway side to protect the wire, it's only really $10 more to have it put in at that price.

 

big open end wrench works just fine, dont waste money on the special socket. put some penetrating oil on it and push on the wrench, it will come out, just needs some muscle. works better if your pipes are hot, but they tend to cool off very fast so get cranking as soon as u can. unplugging the connector without burning yourself on the hot engine is another story.