It heats fine then when come to stop and idle it gets cold

Hello, does the problem happen in slower traffic or sitting still? Or does it happen more when driving? You could have a cooling fan issue if it's when stopped or slow. You could have a thermostat issue if when driving along at normal speeds. Also check for an air pocket in your cooling system, if work has already been done. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops