fuel gauge issue

[jsr86]

so every once and a while when i fill up the fuel gauge goes up to just under 3/4 tank mark and then stops. i can drive it around, turn the truck on and off a few times and it still doesnt show full like it should. the only way i can fix it is disconnecting the batteries fo a few min. after i hook them back up and start the truck the fuel gauge perks up to full. anyone have this isue or know how to fix it?

[bigcountrysg]

Most likely your sending unit