i had a problem a bit like that and it turned out to be glass in the pump. you can try a few goes with a dishwasher cleaner which helped for a while, or you can turn the machine upside down, take off the bottom and take out the pump. Theres a lot of tube and wires so make a note of what you do. if you shine a bright light into the hole of the pump you may see fragments of something. you cant dismantle the pump itself so you have to lever bits out with a screwdriver. this worked for me but i cant say if it is relevant to you
gortonandy
January 2005