My 07 Monte Carlo heat only works when i accelerate if i start in the morning to warm up heat blows cold any suggestions?

The heater in your vehicle produces heat from a heater core. The heater core is a small radiator, located under the dashboard of the vehicle which consists of conductive metal with cooling fins to increase surface area. Hot coolant passing through the heater core gives off heat before returning to the engine cooling circuit. The fan for the vehicle's ventilation system forces air through the heater core to transfer heat from the coolant to the cabin air, which is directed into the vehicle through the vents. If there is a lack of hot coolant running through the heater core or less common, a pocket of air trapped in your heater core, the vents will not produce hot air. It is crucial that you immediately check the level of the antifreeze in your radiator and fill it until it is full. Then monitor it and check for leaks. Running an engine without coolant can lead to expensive or irreversible engine problems like head gasket failure or broken/cracked heads or block.