nissan tino MOT fail on emissions?

I have a 03 reg petrol 1.8 tino. The engine management light came on 3 weeks ago. I had it coded and it came up with the lambda sensor. 2 days later it went off. It drives fine. Took it for the mot yesterday and it failed on emissions. CO was 9.17 and the limit was 0.30. The mechanic said to me it was getting to much fuel and it was dumping it out of the exhaust. This is why the fault was saying lambda sensor as the fuel is wetting the sensor. It is using a lot of fuel.

andy
April 2013