first off just don't go replacing parts that might not need to be changed
find out what the cel is for, that should tell you exactly what is wrong and what to replace/fix
if not people here can direct you in the correct direction and you will find a hopefully easy way out
example, you might get a code that says the cat is dying but you also get a O2 code, well fix the O2 and the other one will go away also....
