Axiom fuel guage issue
 

Hello,
Just in the last week, the fuel gauge in my 2002 Axiom goes to E and the light comes on when the car is sitting at idle. This happened while in a bank drive through and again today at a stop light. The first time, the gauge read half full. Today it was at a quarter full. Both times the gauge returned to the correct reading when I drove off, although it took a couple of minutes to reset. Any ideas what the issue is? Perhaps the sending unit? --TIA