WHAT IS THE EASIST WAY TO CHANG THE O2 SENSOR ON A 91 FIREBIRD? FROM UNDER THE HOOD OR UNDER THE CAR

 

If you have the tool to remove it, I found it to be about the same either way. You'll spend about the same amount of time doing it either way. I usually just do it from the top.

 

get the right tool from autozone. i did it from the top quick and easy

 

Get a 7/8 O2 socket, swivel socket, and have enough extensions. Go from under the car and start from the front of the motor mount. That is what I have found to be the best. But I can also use a lift. The big key is the swivel socket.