If its the 3rd pic down you are talking about its part of the automatic gas recirculation system. The solenoid gets energised at some time (think its either idle or deceleration) and allows fuel vapours to be sucked through the charcoal cannister and back to the tank for stupid emissions legislation. Never had one of these on a car for more than 1 month before ripping it out.
Cheers John top man ! don't need to worry about it then ?