Your heater gets cold when you decelerate but stays warm when im driving What is wrong with your car?

If your heater gets cold when decelerating but stays warm while driving, it may indicate a problem with the coolant flow. This could be due to a stuck thermostat, an airlock in the cooling system, or a failing water pump. Additionally, low coolant levels or a blockage in the heater core could also be causing this issue. It's advisable to have the cooling system inspected to identify and resolve the problem.