Why would my gas gauge stop working after a fill up? on 1990 Buick LeSabre

My gas gauge was working fine. I went in to fill up my car and after I was done the gauge only read a half a tank. I know the car is full of gas. Do you have any ideas what it could be? Thanks.

Asked by for the 1990 Buick LeSabre
1 answer 2 comments
The in tank sending unit is most likely the cluprit!
Crap! Its going to be one of those days. Oh well. Thanks.
U welcom,, sorry!
At least it shows the tank is "half full" think positive!
If it works from that point to empty, it's better than not at all.