what is the estimated mpg rating for a 2004 ford focus?

Answer 1

That would depend on which body style and power-train.
You can look up the right one for your vehicle on the EPA's site .
Here is the page with the 2004 Focus
http://www.fueleconomy.gov/feg/bymake/Ford2004.shtml

Answer 2

24 mpg city to a high of 38 mpg