Ok then I won't cut it off...so andrew your saying that theyll just pop out if I apply some pressure on pulling the cover off?

no, I said use a side cutters to pry them out

I don't think they'll pull out. They look like metal rivets to me.

Yea alright I will try this out now..

Yes they are simple metal rivets.
Drill them out and replace them with screws.
That'* what I did. Use a 1/8 bit and if not go to a 3/16"

Are you certain it'* your rear sensor that'* bad? Did you get a code?

Alright thanks Silverbullet...what type of screw did you use? Stainless Steal? and what length?

Yea I went to Autozone and they scanned it then type the code in there computer and it said the rear one ( actaully said cataylic 02 sensor )

Do you know exactly what code was thrown? It is possible that the sensor is OK, but the catalytic converter is bad.

I don't remember it now, i got it scanned at 12...only thing I remember was the letter P involved in it..I watched the guy look it up and it came right up to the sensor..even watch him scan it...it said cataylic 02 censor back i think..

Also I never changed the sensor and it was 117kmiles on it