Get a GOOD manual on the car and a good meter. Check all sensors according to the book. Clean each sensor connection with Electric part cleaner only, dab a bit of silicon grease on the connection - to seal out moisture and air , to aid assembly and disassembly.
Three runs by the clutch installer to finaly clean and attatch the O2 sensor correctly and clear my CEL(Contour Enthusiasts Light). Check and clean first - its the cheapest thing to do. Replace only what you know is not up to spec....
AND good luck....
