2008 Chevy Equinox Heater issues

What is your question?

I have replaced the thermostat, heater core, and water pump and still have the same issue as before they were replaced. It will blow warm air while you are driving and giving it the gas, but if you let off the gas it blows cold air. The hose to the heater is hot but the hose to the reservoir is cool. It was bleed off to get the air out which took forever and it seems all the air was out but it's still doing the same thing. HELP!!!!

What makes this problem better or worse?

You get warm air only when giving it the gas.

How long has your 2008 Chevrolet Equinox had this problem?

3 winters