I have a 04 ultra with stage 1, 2. After a good yesterday I noticed that behind the a/f backing plate on the efi that there is a tube with nothing on it. It looks as though it is a vacumm inlet of some kind. Is there supposed to be a cap on it or is it supposed to open. I can take a pic if this will help identify the tube and the location. Any and all suggestions are appreciated

 

Should have a rubber cap on it.

 

Thanks I will go to the auto store and get a vacuum cap. I am assuming with this cap off that it was probably running a little lean as well as the idle was off just a bit???