I just replaced my O2 sensor and was wondering if it isnt totally screwed in would it make any difference?When i say not totally screwed in i mean by about a 1/2 to a 1/4 turn or less.I just replaced mine and it runs way different and i am afraid i didnt get it all the way in.I turned it til it wouldnt turn anymore but that doesnt mean its in there all of the way.

 

It should be fine as long as it's not leaking.