We have an LG dishwasher (model ldf6920st) that is 4 years old. It was making a grinding noise during wash cycles. We took everything apart, found two pieces of broken plate, re-assembled and it still made the noise. We ordered a new wash motor and replaced it. The grinding noise is gone but now we have a different noise, maybe best described as a snoring noise. There is no noise, then it starts, increases, holds steady, decreases, holds steady and then stops. It does this many times during the wash cycle, every 20-30 seconds. But not during any other cycle. There are no error codes showing, the wash arms are still spinning and there is nothing blocking any of the holes. We've also gone into the test mode and gone through all of the tests and none of them make the noise. The impeller is able to spin freely and none of the fins are broken. Anything else we can try ourselves? Or is it time to call a repairman?