Contour/Mystique gas guages are funny little things. At least on mine. Mine doesnt move till 3/4 then it drops from 3/4 to 1/4 in about 50 miles...then its really slow to go to E. Maybe your guage is going out
E0 #4384 of 6535
Born Jan. 9 1998
My SVT from the ashes
147,466 miles, purchased Nov. 2002 @ 76,559 miles