I need to replace the oxygen sensor in my 01 SLS, and am not a super car guy. Any advice? I've replaced them on Buicks in the past, so I know I can do it, but with this massive Northstar engine packed into such a small space, I do not even know where it is. Can anyone give me some guidance one where it is located and what steps I need to take to get to it? Or is it buried so far in there that I should pay someone to do it. Any advice would be appreciated. Thanks all.