After running the engine for about 10 min the engine temp needle will slowly begin to creep up. I've checked to see that the fan is op and it is. Replaced the engine coolant temperature sensor thinking that may have been the issue (no reading on the multimeter when tested) and I still have the same problem. When it begins to overheat sitting at idle I can place it in park, step on the gas, and the gauge needle begins to move down. Is this a thermostat issue? Thanks.

 

 

UPDATE:

Drove the car around more after replacing the sensor (Duralast SW546) and it stopped overheating after a days use. Fan turns on and off periodically at idle and the temp gauge doesn't rise.

Still will be doing the coolant flush just so I know the last time it was done.