1994 Dodge Ram Van B250. The needle is all over the place, fluctuating and the fuel tank is nearly full and the vehicle runs just fine. What's needed, a replacement sending unit or what? It appears that many pumps include the sending unit. I just purchased a replacement fuel pump at amazon prime, Bosch 67621, for less than $75 delivered. It comes with a built-in sending unit that is not replaceable. I could check the electrical connectivity at the top of the pump/fuel tank to see if something worked loose. Is there something that I'm overlooking?