Aeromotive Stealth Tank

[Tnfastbk]

I have installed a new aeromotive stealth tank with an internal fuel pump. I also just installed new Dakota Digital VHX gauges. Everything seems to work properly except the gas gauge. It will read properly when first starting the car. When I start to back out of the driveway it may drop 1/2 tank or better, while driving drops to empty. I have talked to Aeromotive and Dakota and get a different answer every time I call. If anyone has any wiring knowledge of this setup please share it. It only has a three post set up on the tank. A +, -, and a signal post. I think its a grounding issue but cant find the right combination. Also the tank is grounded with a chassis ground. The instructions a pretty clear on the power set up but not the sending unit, The pump works and drive fine its just the sending unit is flakey.