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.
I did some more research and found a discussion thread on this exact problem with this response:
“The fuel level sensor is faulty. The sensor has small metal contact that eventually wear down or burn off. Very common issue from about '97-about '06 on GM vehicles. The sensor can be replaced separately from the fuel pump assembly. You can expect to pay about 2.5 hours in labor, and I’m guessing around $120 for the part.”
That is correct, I’ve had the same problem with my 2000 Blazer for a few years now. I keep track of the mileage between fill-ups and have a good idea how far I can go (~240-250 mile) and still have ~3 gallons left in the tank.
I hardly ever let my cars get below a half tank before filling up. So looks like either shell out about $300 for a new sensor, or just fill it up more often.