try replacing the sensor? If you had that much sludge in the oil pan, you probably need to at least pull the sensor and clean the passage it sits in.

If you have been running the wrong viscosity for the temperatures in arizona. (there might be a 10-20w difference due to temp) then you might might need to step back down to the appropriate thicker oil.

If you are having such a sludging problem then you might have a sludge problem in the head too.