I recently adjusted my gearbox on the steering to take up some of the slack. I turned the adjustment screw about 1/8th of a turn in. I don't exactly remember how the steering was prior to this because I had to correct the car a lot do to the slack in the steering. After the adjustment I noticed that the steering wheel will return to center but not quite center. It will go back most of the way but it will slow down when it has 1/4th of a turn left till complete center and thats where I have to correct it. Is this normal?

Also, my steering is heavier when its cold than when the car is completely warmed up. The ambient temperatures range from 24F-40F. It is noticeable when its very cold.