I've had a squeaking noise in the passenger side IP area since I got the car used a few months ago. Looked into it today and discovered the problem. There is plastic bottom piece under the passenger side IP... basically right above where your feet are. This plastic piece is only secured by two of those plastic clip fastners... so it is able to move. In the back of this plastic cover there are two molded in plastic posts that insert into two holes. These two posts rub against the holes they are inserted into and cause the squeak. Wrapped it with some tape and stuck the posts back in and clipped it back up. NO SQUEAK NOW!