Are you heading in the right direction?
Over time, the magnetic headings of runways change. Using modern charts in Flight Simulation creates a problem.Your chart tells you to fly 269 degrees, your ILS captures the localiser, but as you come out of the low cloud, you always seem to be off the centreline. Throwing the aircraft around trying to do that last second correction before hitting the PAPI lights is not comfortable for your virtual passengers.
Given the age of the simulators we use, this magnetic variation means the course can be a few degrees out. Thankfully, there is a cure. Download an updated mag file from this site:
There are versions for FS2004 (FS9) and FSX. Instructions are included and it is a simple case of backing up your existing file and replacing it with the one supplied. If you are using X-Plane 10 then you have no need to worry as the mag data is up to date.