Kenmore Dishwashing not working properly.

Question

My dishwasher is not washing properly or rinsing properly and at times does not drain properly. We have had the "Sears Expert" in twice and they say that it is our problem because the hose from the dishwasher to the sink is kinking and therefore the dishwasher is not washing and rinsing properly. We have been paying extended warranty for a number of years and they will not fix it. I have checked and double checked while the dishwasher is running and rinsing and emptying and it is not a "kink" in our hose. Do you know what the problem might be so I can call Sears and get the "expert" back in to fix it? Thanks Lana