New owner here but similar problem on my 2007 Allure (LaCrosse). I had noticed the gauge acting strangely, and ended up out of gas on the side of the road once. Made me upset, but I got gas from a farmer and went off wondering how I couldn't have noticed that I was out of gas. Oh well. All'* well that ends well.
Last night I was responding to a panicked call from my Daughter begging to help when I ended up stranded o nte side of a country road. The fuel gauge showed 1/4 tank, but the car was dead. Having only had the car for afew weeks, I was upset that this "new-to-me" GM Optimum car was letting me down so quickly.
Activated on-star and got roadside assistance to take the car to the nearest dealer. Got a call from the dealer this morning that they will replace the fuel pump for $1300.
This morning I thought through the last week and it occurred to me that its been about 4 days since I filled up. In that time I have travelled about 600 km - a tankful of gas. I am betting the tank is just empty and the sending unit is faulty.
In searching for solutions/similar problems I came across your post, and this article from consumer reports: http://consumerguideauto.howstuffwor...lacrosse-2.htm