I don't have an answer for this but I am having the same problem with my Whirlpool ADP5550.
Washes for a certain amount of time then makes a lot of noise sounds like a pump is stopping/starting. Then my pipes knock a bit and after a couple of minutes the dishwasher stops with F8.
Already had a technician out who ran the self test which went through fine. He told me to change the powder I am using and not use rinse aid - nothing he said has worked.
Whirlpool support is rubbish, if the self test goes through okay which it does ( big deal ) they will say there is no problem and charge you.
Anyone got any ideas here? I have checked the filter and am about to throw this thing in the river.
DJ Spank
January 2006