My car has been stuttering when I come to a stop and the check engine light came on, so I took it to get a read on the computer at Autozone. The computer says that both if not all 02 sensors are not working. My question is where are the 02 sensors located on a 08 galant ES 2.4 and should I attempt to change them myself or would it be better to take it to a shop? Thanks for any imput