The rubber seal onour oil cap may also be worn out, so that thids maybe the cause of a continuos vacuum leak.
regards,
Steve

 

The idle on my SC changes and it runs rough when the oil cap is removed. This is normal and is due to creating an air leak into the CIS system. If the idle on your SC doesn't change then you probably have an air leak somewhere else. I would check this out, as you don't want your car to run lean. Good luck.