Howdy...my car just failed it's MOT due to emissions

During the fast idle test (of which they did two) the CO level got to 0.59%@2951 RPM and 0.39%@2834 RPM.
Last year my reading was 0.27%@2565 RPM. Oil temperature was 84deg. Lambda and HC readings were fine.

Also my natural idle RPM is higher @812 RPM compared to 683 RPM last year - although it did pass the CO test @ idle.

My exhaust setup is the same as it was last year, Ninja downpipe with sports cat, de-cat centre and racebox backbox (UK classic)
I have however had a remap from Simon since my last MOT - does this account for the variation? (more fuel in = more CO out?)

Do I just need to get a catted centre from somewhere and slap it on for MOT time or is this an indication of another problem?
What can I do about the natural idle? Clean the ICV? Anything else?

Any advice/comments are very welcome.

 

Could be any number of things though i doubt the remap is one. Try and get a center would be my first choice m8 they can be had for buttons if you cant borrow one of a sn'er up your way.

 

What MY is it ?? could be maf issues

 

MY00. I replaced the MAF last summer and I don't have any problems under boost.

 

i just take out my air filter thats normaly works while on MOT then pop back in after

 

I know if you remove one HT lead run it for 2-3mins it super heats the cat, then get them to check it as soon as you put the lead back on and it should pass.

 

this is the lazy mans alternative to the old "rag it to the mot station" advice

supposed to work too

 

If it passes the MOT you can't complain really.
I heard of a few people failing with the Ninja sports cat fitted.

 

ive heard u can put red ex in the tank an will pass. just dunno if destroys injectors