My Duratec engined +4 just failed its MOT on missions. It had a HC level of 279 at fast idle (limit 200) and a CO of 3.85 (limit 0.3) and at idle a CO of 8.16 (limit 0.5).
Apart from losing some crispness to the exhaust note through being too rich, there is no notable change in running or performance.
The OBD put a question over the lambda before the CAT, but changing that didn't make any difference. The CAT look OK?
Anyone got any ideas?
