High CO output & lambda sensors

[pj_sibley]

I recently did a rolling road session with my S4 and my CO emissions on idle, both before and after the runs, were approaching the MoT limit. A little bit concerning, although the MoT isn't due for a while.

A friend suggested that this could be due to one or a combination of a few things:

- Faulty MAF sensor
- Faulty lambda sensor
- Faulty EGT sensor

My car is one of the 'b*stard' cars i.e. 1999 T-plate with facelift exterior and pre-facelift interior with analogue clock. Am I correct in thinking I will therefore have 2 lambda sensors (1 on each downpipe) and 2 or 4 EGT sensors??

Any advice much appreciated!

[S4]

Just 1 02.....only the very very last had 4 fitted.


Darren

[imolas4uk]

2 lambdas and 2 EGT`s

[pj_sibley]

Thanks for clarifying that

Any thoughts on what might be causing the high CO readings? I don't really want to spend the money replacing the MAF / Lambda / EGTs if I could just give the MAF a good clean?