My 02 q45 keeps reading misfire on cylinder 2 I've changed the plug coil and

So is this a easy fix or just throw the towel in also what other problems could this because besides that the car drives good going down the road

I don't work on Infiniti's but, the process should be similar and the cost should not be too bad. Have they checked the valve to make sure there isn't an issue there. You may wish to ask them. Or a compression check?