Kenmore 90 series Model#110.22902100

My washer is a top load washer and my problem is when I start a cycle the water starts to fill but my agitator starts immediately also. When the water reaches the selected fill level the water turns off and the agitator continues for about 10 seconds and then shuts off. it will stay off for about 5 minutes or so and then begin to agitate again for about 10 seconds. it will continue to do this until I manually advance the timer. I have tried cleaning my pressure tube and added a little vinegar in the tube but that did not help

any suggestions