My Yaris is due for an MOT this month. The last MOT report says that CO is right on the limit, everything else is normal HC, Lambda etc., as shown below.
The CO has been creeping up every year, and the code P0172 has recently came up which means "System Too Rich".
The car is 19 years old and when it's first started I can smell petrol outside and sometimes when I get out after driving it I can smell it too. I've tried Cataclean and i've also cleaned the MAF.
I'm thinking it's the CAT? Any thoughts?