Hey newbie...
First off the FAQ is a place to search for answers to the most common questions we've seen here and decided to archive... it's not for general posting, so I've moved your thread to the parent group where it belongs.
Identifying a part is pretty hard without more specifics... hell, even knowing which side it's on can make a nice big difference but better yet would be the part number off of it or some photos.
No a miss at idle isn't normal. Start with checking for vacuum leaks, inspect spark plugs and wires.