If it has one, its just spinning, but its not used. Personnaly, I have never seen one on a Fox Body stang. Makes no sense to have one, if not running a Mechanical pump. Regardless, no mechanical pump that I know of, that is used on a engine can generate the fuel requirements of standard EFI systems. Which is about 40-60psi. Why there would be and eccentric on the Cam of and EFI engine, is beyond me.