Dave Harney
You mentioned that the front 2 02 sensors weren't switching very much on live data, can you verify this by testing the 02 sensors either with a scope or voltmeter ?
I think your C02 is slightly low, the cat could be clearing up the C0 and HC's so masking a possible fault.
Testing the pre-cat 02 sensors and fuel trim figures should give you a guide if you are looking for a fault engine side or exhaust side.
Regards
Dave
You can trim a sheeps wool many times, but you can only fleece it once !
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Ford Focus 1.6 2008 - MOT Emission failure - Fixed # - Paul Goswell May 19, 2015, 9:35 am
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