On a resent 1250 mile round trip my 1994 Taurus GL 4 Dr with 8.3L SFI
engine got 21.717 MPG highway driving. Driving conditions where
65-70 MPH with cruise control, 50-60 degrees outside temp. Milage
on the car is 117K with all schedule maintence preformed. Engine
starts, idles and runs smooth. Also trip was in two (2) days about
600+ miles each day. This car is new to me but I do have the
scheduled maintence records which show it was serviced per Ford's
recommendations.
Is this low gas milage normal or should I have some thing serviced?

I think you are talking about your 3.8L engine, 21 mpg I think it is normal.
I am driving a 97 Taurus and most of time the mpg is around 21.