I know this has been discussed a million times, but I really just want to verify everything that I have read.
Firts I have a CEL and I know the codes are P1405 and P0420.
I have read everything about them in the archives and it seems like every contour has had them at some point in time! I am pretty sure the cat is bad because you can hear the plates rattle together when I accelerate!
My main question is, I plan to have a shop put on the zetec headers for a focus, which I have read will fit the contour with slight mods,then put a standard hi-flow cat on, but should I go ahead and replace the O2 sensors while I am at it???
How many of them are there, 4 or 2, and which ones do you guys recommend I replace, all of them or some of them or what?
Any help would be great!
Thanks
