I'll bet it's the same fuel sending unit problem on all the Minivans. The fuel sending unit is dirty or damaged, which means: replace the fuel pump assembly (which has the sending unit on it, just like the minivans)
I have one in my Caravan that reads dead empty, but only when full, then dings and goes back and forth until the tank is just under full (like 1/2 a gallon down), then it works perfectly. It's Been that way for 10 years... never got better, never gotten worse. I just left it alone and ignore the ding and low fuel light for the first 18 miles or so. (because I'm too cheap to replace the fuel pump, for a sending unit failure).