My manual doesn't match up with our model number ~ diswasher isn't akways draining properly and is leaving hardened residue on the dishes. Can't seem to find the soil removal system. Any suggestions?

Sounds like the pump isn't working properly, being how its not draining, or washing properly. Does it sound like it has a good powerful "whoosh" when its running?

If not, then the pump impeller, or hose assemblies could be partially clogged.