Have only had my 2013 EcoBoost MKS since December. With factory warranty I have not been doing any work myself but have now started checking things since the dealer massively over filled the engine oil!
Found this plug sitting wide open under the engine cover. Can anyone tell me what it is? I have the service CD and have looked but can't find any mention of it??

Found this plug sitting wide open under the engine cover. Can anyone tell me what it is? I have the service CD and have looked but can't find any mention of it??
