It's a little black cylinder located on the engine side of the firewall and has one hose connecting it to the check valve, which ultimately has a hose connecting to the vacuum pressure of the cylinder head. I broke the nozzle on the top off and then I kind of hot glued the vacuum tube onto the hole. Somehow it actually works. Anyway, does anyone know the function of this thing so I can figure out whether I need to replace it or not?