I have the 1.8litre 2009 astra and one of the wires broke off of the o2 sensor right at the base of it and ive been having a bad misfire im not sure if its the cause as there is a number of issues the car has that need fixed but am curious if this could cause a misfire ive heard the upper sensor is the more critical one so just checking if the lower one could cause misfires

 

That is not your misfire. What codes?