172 failed mot on emisions

[hoperacing]

car has failed on emisions and we cant figure it out. co2 reading way to high. cat fine and flys through one revs up above 2.5 k but wont go through on idle. he says there is some noise coming from top end thinks possible cam bearig problem. i never heard anything when i gave him it though?
any ideas

 

[Djw John]

Was it warmed up and given a good blasting before going there? Usually helps

 

[edde]

Might be the lambeda sensor.

 

[hoperacing]

lambda is fine.
yeah was warmed

 

[tomhunt85]

What was the reading out of interest?

 

[mattih5]

Just out of curiosity what is a good reading? I had a 48k service done not long back and RS Tuning gave me a bit of paper with emission readings on. I've got my MOT next Friday.

 

[Batman]

the engine was warm but did you give it some good beanage? i took mine out and flew round like i was on "the ring" and mine went through fine