Whirlpool Gold dishwasher

I have a Whirlpool Gold Quiet Partner 3 dishwasher. Lately, the dishes on the top rack do not get clean. It appears that there is no water getting to the top. I've checked the screen/filter on the inside-bottom of the machine and it's clean, as are the pipes that would normally bring the water to the top. Does this sound like it is the pump, or is there something else that I should be looking into ? Is this an issue that I can repair (I'm fairly handy) or do I need to call a repairman ? Please help. Thanks, Sod07 I have a Whirlpool Gold dishwasher about a year old and have problems with the detergent not dissolving. It gets all over the silverware and I have to hand wash ... and scrub... to get it off. It also leaves a white residue on the glasses. I have tried different types of detergents... powder, liquid and the tablets that have the rinse agent in them,,, and have had the same results. The guy who sold me the machine suggested that I move the silverware rack off the door onto the rack but the results are even worse. Does anyone have any suggestions?