2006 Chrysler Pacifica engine problem

I've never run into this on such a new vehicle, but it was real common in the '90s. That's assuming the gauge starts to work again when the tank gets to around 1/4. The cause is weak tension on the movable contact on the float arm for the fuel level sending unit. Most people replace the sending unit, then risk having the same problem in a few years.

The better repair is to remove the pump assembly, unclip the float arm, then bend the contact slightly to put more pressure on it.

Apparently you didn't read all of my comments. This used to be a common problem, including with replacement parts. You can replace the entire expensive fuel pump assembly if you want to, then risk having the same problem in a few years, or you can perform the much more reliable and inexpensive repair which is to simply tighten the movable contact on the float arm.