850T, 73k
Wed PM - Ck engine lt came on while on hwy, no driveability issues.
Thurs AM/PM - Drove to/from work (20mi hwy each way) without issue.
Thurs PM - Checked codes from port A2 - showed 3-1-5 code (Evap). Cleared fault, started car, fault didn't return.
Fri AM - Drove to work, all hwy, outside temp 25F, heard fan come on on hwy, temp gauge at 3/4 position. Cooled down to 3-o'clock position as exited hwy and fan ran, fan continued to run till shut car off.

Fri PM - Drove home outside temp 29F, temp gauge somewhat erratic, fan on when gauge reading high temp, off when reading normal temp. Temp gauge stable at idle/slow speed, but reading high/overtemp (almost in the red) when accelerating/maintaining hwy speeds. Inverse of any true cooling problem I have seen.
At home, left car running, temp gauge running higher than normal temp (almost to red zone), fan running. Engine feels warm but not hot, top rad hose warm but not hot, rad body warm but not hot, bottom rad hose cool/cold. Shut car off, fan continued to run for 5 mins then shut down.

If top rad hose is warm and bottom is cool, rad/fan is working yet temp sensor/gauge didn't seem to respond. Coolant level is fine, been about 20k since last coolant change. If thermostat were sticking closed, would indicated temp rise more when accelerating/driving and cool down when idling/sitting still??

Help! I have a new thermo but have to order the temp sensor...don't want to tear it apart tonight if I can't get the sensor till Mon/Tues.