Great potential, some nagging fuel problems

Having had five Ford products previously and virtually no serious repairs ever, I felt comfortable trading my ten year old Escort for a Focus Wagon SEL model (4 cyl, 5-sp).
The first year has been virtually trouble free, and the car remains tight, peppy and fun to drive. The "winter accessory package" included heated seats (wife loves them), traction control and block heater but came with the most brutal all season tires that I have ever driven on (had to buy real winter tires when the first snow fell - the stock tires were lethally dangerous in the snow).
Wife wanted to buy a Subaru Outback or Jetta TD wagon, but my 6'5" height made this impossible - I couldn't fit in the Subaru to drive it, and the Jetta, while comfortable to drive had no room behind me for passengers while I was driving. The Focus had much more and is quite comfortable for day-long family drives.
The biggest problems are fuel and fuel management related. The fuel gauge reads empty when there is still 1/3rd of a tank left and the fuel mileage after one year is the worst of any 4cyl that I have ever owned and ranks average for some 6-cyl that I have owned. Though rated for 31mpg city/ 42mpg hwy (CDN gallons), I have been averaging 21.9 city and 28.8 hwy. These two issues combined, leave me with a empty fuel light coming on after less than 300km (190miles) in the city. In contrast, my Escort returned a 10-yr average of 29.9 city/40.5 hwy and the two had nearly identical EPA estimates on the window sticker so there is a problem here. Also, the car refuses to start about 2 or 3 times every month and occasionally loses power for no reason and the service department cannot recreate or solve the problem. I think the mileage/engine problems/fuel gauge are all part of the same problem with the fuel system, but no solution yet.
Otherwise, this is a great car and depending on how the next year pans out with the above problems, I would likely keep it or buy another.