would appreciate feedback ON 2001 olds silhouette van

my mother just purchased a used 2001 olds silhouette van 70k miles on it. i was just wondering if anyone has had any experience with this vehicle. she brought it home tonight and already the gas gauge is acting up. it was idling and the gas gauge dropped down almost to e and the low fuel light came on, which i expect this is how this is supposed to work? when the gas needle drops so far that gives the indication for the low fuel light or does that signal come from the sending unit in the gas tank? anyways, when this happened there was approximately a 1/2 tank gas in it. i took it and filled it the rest of the way up and so far the gauge has stayed. could this be an indication the fuel sending unit is on its last leg? does anyone know of any problems with this type of vehicle or do they have a pretty good reputation? any input will be appreciated, thank you

 

you got it if i remember right you can just get the fuel level sensor

 

^ which requires dropping the tank.

 

thanks for the info. i talked to her awhile ago and she said this morning that the battery was dead. she called the guy she bought it from, his mechanic said the fuel gauge acting like that was from the battery going dead. i witnessed the fuel gauge dropping off myself, and none of the other gauges ever moved. i find this hard to believe that none of the other gauges wouldn't have reacted this same way if it were the battery. besides that the vehicle was running, the battery would have been charging right? unless could the alternator be failing?