taxing and gps problems

when i start backing off the plane, press shift + p, and 1 or 2 to turn the tail left or right
the problem is 1 or 2 doesn't work, i pressed it and nothing happens??
i already turn the numlock on or off, no effect
also when i am flying, i set the auto pilot to the right heading, after awhile the plane will not stay in the right course and i have to adjust the heading again, is this right??
the problem is 1 or 2 doesn't work, i pressed it and nothing happens??

also when i am flying, i set the auto pilot to the right heading, after awhile the plane will not stay in the right course and i have to adjust the heading again, is this right??