You said that something was making a horrible noise in the motor, but that it went away on its own. Do you think that something could have been making a horrible noise in the pump and when it went away, it might have been ground into small pieces and that one of them might have gone into the hose feeding the power shower spray? A more than minimal amount of water should make that turn. Can you spin it by flicking it with a finger? If you can't remove the dishwasher from its installed position to remove the hose at the top of the tank, you could stretch a balloon over the end of the sprayer to get an idea of how much water is coming out of it by how fast it fills the balloon. If the flow seems to be inadequate, you would need to remove the lower panel and, with a bowl under the pump, remove the clip for the hose that feeds the upper spray to check for blockage. You might want to get a replacement hose clamp in case the original is one of those cheap ones that cannot be reused.
