Lambda 1.1 is lean. That is assuming the sample probe was far enough up the exhaust not to have been diluted by air being drawn up the tailpipe by exhaust pulses.
If it's hot enough the lambda sensor should have the engine running close to lambda 1.0.
Even if the cat isn't working it will still show lambda 1.0 (or very close) if the top lambda is working. The bottom lambda only monitors cat efficiency.
If you have O2, as well as CO present in the exhaust (or values more than the limit) and the cat should be sufficiently hot then the cat efficiency is low. Sometimes a good thrashing up a hill on the motorway can generate enough heat in the cat for it to improve its efficiency.
Short trips are bad news for cats.
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