When sitting at light car runs hot, when moving car stop running hot

Fan/s not coming on when needed. When moving down the road the airflows over radiator cooling off the engine as when sitting still it needs the fan/s to move air through the radiator.

Are you having to add coolant? Run hot after driving short period of time? Or run hot when come to a stop at a red light or sitting still for a couple minutes?

Usually a sign the thermostat is not working correctly, or the radiator is not full of coolant.

Sounds like you might have a fan problem. Check and make sure the fans are functioning properly.

When I have a car that runs hot while moving, cools down sitting I immediately check
the radiator fins for clogging with debris, hair, dirt, bugs.
This is a sort of easy fix and you do not have to buy parts.
Drain the radiator and save the fluid.
Remove the radiator and hold it up to the light.
If you cannot see through it easily then start washing the outside and the fins.
I use water pressure, air, and a shop vac to clean the cooling fins.
Taking the radiator to a shop where they hot tank it accomplishes the same thing.
There is a product for cleaning the radiator fins, but I have never needed it.
The good news is a new radiator is probably not needed.
This assumes that you have never used a stop leak product inside and have
only used anti-freeze/water.
You might be able to clean the radiator fins without removing it , try water and soap.

Sounds to me you may have a small hole in head gasket. You need to take and have pressure tested to make sure, Best of luck to you.

That sounds like the coolant level is low. If it is not the use of "stop leak" has probably caused a partial clog which restricts the flow of water unless the vehicle is turning higher RPMS. While sitting still raise the RPMS to about 2000 and see if the heater blows hot air to see if the above mentioned problems are fact.

Have your a/c condensor fan check out, sit in back of the radiator, fan should always be on when a/c is on to reduce the freon pressure in the condensor or a/c will not get cold till air goes through the condensor while driving down the road, no air blows through at stop light because fan not working so a/c will not work right.

Vacume leak or bad idle motor. With the car in park and running with the hood open listen for leaks moving your hand around the different hoses looking for a change in the sounds that you hear. The idel motor also makes the car idel up to 1500 RPM or so right at start-up then idel down, If it doesn;t the idel motor is likly. Check engine light is on when running? Test for codes, Follow code test charts don't skip any steps!.

check that your radiator fans are working. what is happening is that when you are stopped, your pump is having a pressure build up since the freon isn't being cooled and possibly the pump will stop spinning and start to screech because of the pressure. When you are moving the fans don't need to run and the freon is being cooled and so everything is working normally. Your fans should turn on while sitting still for a few minutes. If your engine temp is over half, they should be on. Let me know if you have any other questions with this