discussion before was that the gas guages were programmed to work that way, it should be slow to 3/4s then dive to 1/4 then level off some
and you should be recording your milage, like I know I can get 350 at best on winter gas in my mystique and somewhere between 350 and 375 on summer gas per tank
on my contour I know I should get about 300 mile per tank
