Aircraft banks left and right with APR on

I have a problem with my aircraft banking left and right at about once every 3 seconds. When I am approaching the ILS with the APR button depressed but not on the glide slope, the aircraft starts a slow right and left banking for some reason or another. I wonder if anyone else has had a problem like this and what the corrective action is. I am not sure if it can be corrected in the aircraft.cfg file or not. It makes it impossible to land the aircraft under these conditions even when locked to the glideslope.