Been having troubles getting my car to pass MOT emissions.

Failed on CO (double the limits) and Lambda (a teeny bit over)

It's failed twice, the lamda improved second time as I fixed loads of blow holes in the exhaust. now lambda was only 0.006 over the limit. my main worry is the CO (still double).



I've just noticed that the exhaust manifold has a little gap between it and the block. I think it's leaking exhaust gases..
Would this trick Lambda sensor into thinking mixture was too lean (due to air entering system)..
And so make ECU richen the mixture
Hence causing higher CO levels?

Does this make sense? It's on a Polo as with my previous thread, have tried asking for advice on Club Polo but they are such scene queens I haven't got an answer lol

All help and advice muchos appreciated

Thanks, Chris