My car has been rattling and there was oil in one of the sparkplugs
Hello there, without know your year, make, and model I can only offer general advice. When oil is seen on the spark plugs it is most often due to the valve cover gaskets leaking. The valve covers have seals around the spark plug tubes and over time these seals can leak filling the spark plug tubes up with oil. The rattling can be caused by many faults but an engine that is misfiring due to oil on the plugs can have a rattle noise. A qualified Technician such as one from YourMechanic will be able to diagnose your engine rattle and inspect the spark plugs to determine why they have oil on them.
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