This concern is most likely caused by a bad fuel level sensor. This is the sensor in the fuel tank that reads the fuel level and sends the information to the cars computer. When this sensor goes bad, you fuel gauge will not read correctly and may also set a code p0463 and my turn on your check engine light.
To repair this concern, you would need to replace the sensor. To do this,you would need to remove the fuel tank and fuel pump, the sensor is located on the pump.
Let me know if you need more information on t his issue.
This sounds more like a fuel sensor issue. The fuel moves around when you turn the car and the sensor moves around. The sensor more then likely has a BAD spot that is causing the issue and when the sensor moves around, it goes to a good spot. Same type of issue when you fill or the tank becomes low on fuel. This is not uncommon on these cars to have this issue. Normally when the gauge itself is bad, the gauge will just stick in one place all the time. Also if the low fuel warning comes on, this is another hint that the sensor is bad.