This is probably a stupid easy question for you guys.  But I'm new to owning a 280z.  I have a 78 by the way.  My question is I'm unfamiliar with how the gas gauge is supposed to operate.  I know it's a float unit and I've never owned a car with one before.  Mine for example right now is on just above slightly a half a tank.  But while I'm driving or even sitting still it moves a little, not much, just sometimes it's a half, then maybe a few seconds later it's just above a half slightly where it