I had the MOT on my G40 a few months ago and the MOT came back with a CO of around 3.5% which was a bit of a surprise. Fortunately, because of the age of the car, it was just within the pass limit. The CO reading at MOT time is usually around 0.02% (yep, it's a little lean at idle and needs a remap).
Anyway, the car only does a few hundred miles between MOT's, so I'm guessing something has suddenly failed as opposed to the slow deterioration of something. Before I get cracking to get to the bottom of this, can anyone suggest what I should be looking at as likely faulty components? The engine has around 10k miles on it and was rebuilt just under 10 years ago. The serviceable ignition components (HT leads, plugs, dizzy etc) are all this age/mileage. Am I right to assume the blue temp sensor could be a likely candidate?
It's also worth noting that the cable for the fan broke and I noticed the coolant temperature went up to 120c during the emissions test before I noticed it. Could that have had any bearing on this during the test?
Thanks :)