Stumped

I'm having sending unit problems. New sending unit. I have done all the fuel gauge tests and the guage works. I have voltage to sending unit. I'm grounded to the same place as my fuel pump and it works fine. I've put my multimeter on everything and its all checking out. I even pulled the sending unit out and tested it and it ran the scale like it should.
I can ground it out and the fuel guage will move. I'm out of ideas , maybe the sending unit is faulty?