I am embarrassed to say that I am having trouble getting the 16mm socket on the #2 spark plug. This is a 1995 Cabrio 2.0L. It is a tight fit but the other three all came out no problem. It seems the cavity for the #2 plug is more narrow than the others. Is this true? Is a special socket required? If so where can I get one. I have searched and cannot find any reference to anyone else having this problem.