MOT Failure CO emisisons at idle - New MAF needed
 

Just a post for reference, may be useful to anybody searching the forum in the future.

My standard MY99 failed it's MOT on the Natural Idle CO emissions. Fast idle passed. Did my homework and suspected the O2 sensor and changed it, no difference. Changed the MAF - result, emissions are practically non existent.

Hope this proves useful.

Thanks to Dark Blue Mark for is advice.

It's usually down to one or the other. A failing MAF is not good as it can lead to the fuel/air mix leaning out on boost. This leads to detonation = blown engine.

Some people change them anually for piece of mind.

;)

Glad its sorted.

MB