Fuel-filler area weird electro-mechanical noisearea
 

So when I approach my vehicle, and as I lift the door handle (so I guess when electrics kick in as window does the drop), an elecro-mechanical whirring noise (not the soda bottle or whooshing that folks talk about) starts coming from the fuel filler area. Seems to last literally 30 seconds and then switches off. It also seems to have given me a rough idle as the problem happened simultaneously I believe so am not driving the car. I know it sounds like a failing fuel pump but have removed relay and fuse, and opened up under battery, and when the noise happens, pump is quiet so definitely not the fuel pump. Is there anything electric in the canister perhaps that could make the noise?

Any help solving my mystery appreciated :)