oil pressure??

ok oil pressure is dropping to 0 at idle in drivre, shift the car into neutral idle comes up about 200 rpm and the oil pressure shoots up to under 200, basically where it sits when you're driving the car. any ideas??? sending unit, or the actual oil pump??

From the dashboard view? like the oil pressure light coming on, or actual oil pressure taken from engine block ?

from the dasboard view. haven't taken it from the engine block yet. the gauge is sporatic, that's why i think it's the sending unit.