The fuel level sender can malfunction causing the fuel gauge to always read at the full level.
Car Problem Reports
Saab 9-7x Fuel Gauge Always Reads Full
Saab 9-7x Problem
Electrical & Lights Affected: 4.2L 6 Cylinder, 5.3L V8
Average Mileage: 70,750 mi (37,000 mi - 130,000 mi)
Visitor, 2007 Saab 9-7x, 79,000 mi
I pull into the gas station without the fuel light on, then I leave the gas pump after putting 20 gallons in it and the low fuel light is on as well as the check engine light. I was reading on line that GM is taking care of half the cost of the fuel pump/sending unit / sensor as it is all one part.
Visitor, 2007 Saab 9-7x, 41,000 mi
when tank is half full, the light comes on and registered empty. This has happened twice straight
Visitor, 2006 Saab 9-7x
Fuel gauge reads empty when tank is full. Engine light comes on as it does this.
Visitor, 2006 Saab 9-7x, 45,000 mi
Fuel gauge malfunction. When tank filled gauge reads empty. As fuel is used gauge operates more effectively. Service engine light periodically comes on due to "low Fuel level" $500 to $600 repair estimate
I changed the fuel level sender (involves dropping the fuel tank) with a new sender and the problem was solved.
Visitor, 2006 Saab 9-7x, 72,000 mi
Fuel sensor went bad, Fuel level in car goes from full to empty sporadically