Mechanic help! MOT Failed?

Question

I have a T reg citroen saxo 1.1i. It has failed the mot for 'Exhaust emissions carbon monoxide content at idle excessive 7.3.2c'

I had a new cat and exhaust put in last year which didnt change the problem, as the exhaust seems to make a popping noise and you can often smell the fumes, it also floods a lot and ownt start, we have changed the fuel injector which didnt make a difference, have changed the spark plugs which helped slightly but didnt get rid of this ongoing problem. do you think its the sensors? if so are they exepensive to buy from a shop so my boyfriend can change them and is it hard to do? or shall i take the car to citroen and ask them for a quote so they can at least tell me where the problem lies?

Answer 1

Taking it in for a quote would be a good idea but only if they're willing to do it free of charge.

Sounds like it's running too rich.  Mass air flow sensor will probably fix it but they're not cheap $200 - $300 American.  But they are easy to install.  (it's a pretty expensive guess)

Answer 2

That would be a great idea take it to a shop and run a scan and let them tell you what the problem is.  could be  the IAC or TPS which would cause it to run rich at idle and flood. just a guess on my end