On reflection, do you have minerally water there? If there's a buildup of scale somewhere in the washer, the water may be completely saturated with minerals, so that the detergent doesn't go into solution as it ought. That'd account for slow drying, poor cleaning, and also for the gritty feel that Spaceroo reported. You might try running a couple empty loads with a bottle of CLR or Lime-Away dumped in there.