I have a '97 Catera. I brought the car used and I had it about a month. I haven't had any major issues with the car. One cold morning I went to start the car and my check engine light came on. I went immediately and had the car scanned and the codes came back P0300. The tech said it was was a misfire in cylinder #6 and I should have the car tuned up and the light should go off. I decided to start by changing the spark plugs myself. When I pulled one of the wires out it had a long rubber piece on the end of it and it had oil all over it. As a matter of fact there is a space between the actual cylinder and a black strip of metal that run the length of the head. It was full oil. I wasn't sure about this because I didn't know if any oil was supposed to be here. Can someone tell what's going on?