Hi all retired mechanic old school ! we have had this car from new no problems! recently gave it a full service new exhaust from cat back! new lambda sensor in front pipe ( not the cat ) all good for 4 weeks now have EML light on, no change in the way it drives at all, past mot 3 weeks all good. i am still with the AA do i call them out and get a diagnostic ( if the guys any good) or any ideas please this is new to me .many thanks.