yeah, ironic huh.
This is one of the most important plugs on the quad (well they all are really) and this is the worst fitting plug on the quad.
I have cut the ends off of two wire ties and shoved them down between the plug and socket trying to get a better fit. It didn't work, they vibrated out. Now I don't wedge anything in there but what I have found is this: when you are putting the top shell back on and you plug in the gps cable, as you are lowering the top shell down, make sure to bend the gps cable away from the outside of the quad. Bend it towards the inside. It will hold itself in that way. I don't have gps issues any more, and as an added bonus my camera comes right on every time now. I was fighting my camera, it would only come on half the time. I would re-boot everything then it would work. Now it's first time every time. I have no idea what this gps cable has to do with the camera, but this has been my experience.
try it, it might help