Fuel Computer 1994 Aerostar 2WD 4.0L

[freddyx]

I have an issue with the fuel computer. The issue was not with the speedo head (I don't think), but may be related to that or the fuel sending unit? The gallons of gasoline is acting up and intermittant 2 gallons now 9 gallons later. It is now not reliable and the reading of the average MPG goes up when I know it should be going down. The reading on instant MPG will linger at 99MPG for a while and then work again.

How do these work on a 1994 Ford Aerostar 4.0l 2WD? the dash is all elctronic. Do I need to change the sending unit on the gas tank, or another sensor I am not aware? Cruise, Odometer, and speed is correct.
Thanks in advance!