If your position is off by a few miles then your GPS is not working well enough. How would you ever use it for navigation?
What positioning methods do you have selected? This should be under Settings>General>Positioning.
If you don't have "Integrated GPS" selected, then you are not actually using the GPS antenna. The best method is to have "Integrated GPS" and "Assisted GPS" (or "A-GPS") both selected. This will use a small amount of data (< 5 kB) when getting a position lock, but will speed up lock times considerably.
What positioning methods do you have selected? This should be under Settings>General>Positioning.
If you don't have "Integrated GPS" selected, then you are not actually using the GPS antenna. The best method is to have "Integrated GPS" and "Assisted GPS" (or "A-GPS") both selected. This will use a small amount of data (< 5 kB) when getting a position lock, but will speed up lock times considerably.