I have an 2002 Oldsmobile Intrigue. I started having a problem about a year back where when I first start the engine, if there is 1/4 tank or less left in the gas tank, the gauge will at first show the proper level. However, after driving for a few minutes the gauge will creep up to anywhere from 1/2 to 3/4 fill. I know that the original reading of 1/4 or less is the correct one because of the amount of gas needed to fill the tank. This problem is especially problematic when the tank is almost empty.
Any idea what to ask my mechanic to look for?