Hi everyone, the engine management light on my Fiesta has come on again. Every time it goes to the garage they get the same errors, it reports either the rear lamba sensor or the cat needs replacing. However, the mechanics at the garage have tested the lamba sensor and the cat and they say there isn't a problem with either of them. I am getting tired of taking it back to have them look at it and telling me that it is cured! Wondered if any of you have any suggestions or have had the same problem?