fuel gauge issue, please help!!

[1972BlueC20]

Replaced sending unit, still doesn't work heres what's happening :

This is what happens, when I fill up the needle stays where it was prior to filling up until I drive like 3 miles down the road. Sometimes it even takes till the next day. It then shoots just barely past full. From there it seems to work fairly accurately. It goes down a little everyday as I drive and put more miles on her. Since I'm not sure of the gauge, I always keep track of the miles driven so I don't run out of gas and get stranded on the side of the road. Once I have only about 1-2 estimated gallons left it only goes as far towards empty as a 1/4 of a tank. It may go further down towards empty if I drove somemore, but I'm too scared to run out of gas

When I remove the wire from the sending unit or remove it at the fuse panel there is no change on the fuel gauge.

Anyone have any idea what needs to be fixed or replaced??


Thanks!