Was wondering if anyone else has had this issue and could point me in the direction of a fix.

My fuel gauge is working and on fill up goes to full, after a bit of driving it starts coming down as it should, however after it gets right about to 1/4 of the gauge it goes immediately back up to full. demonic possession or did I wire something wrong? Tried reversing the sending unit wires and then the gauge doesn't work at all.