ok so i just purchased a 2000 civic si 1 day ago and i had to replace the spark plugs right away. when the car engaged vtec the check engine light came on but it still hit vtec with no problems. i took it to autozone to get an obd check and it said that cylinder 1 and 2 were running too rich. it also said that the ignition had a misfire but i think i fixed that problem with the spark plugs. is my problem an o2 sensor? i know a decent amount about hondas but not too much about obd2 since i mostly built crxs. if my problem is that sensor then i know that there are two, which one would it be? to me there too expensive to just guess on unless they are the same in which i also dont know. any help would be appreciated.