Vac Pressure Jumps Up & Down??? Why???

[Rizzie]

When I idle or i noticed if im sitting still and the fans kick on or something, the vac pressure will jump up and down repeatedly from -10 to -21. My pressure stays at -19 at regular though. Anybody might know what this problem is? I checked for leaks everywhere and there isnt one. Thanks in advance

[Garage1217]

VSV valve is opening and closing. Makes the gauge bounce all over all retarded

[Rizzie]

goootcha, what the hell is that lol. is there a way to fix this or what should I try and do?? Thanks