Hey everyone... I hope someone can help...

My 1998 Quest is having a heating problem... As long as I am pressing on the gas, heat is being generated... but if I am idling at a stoplight or just coasting along in neutral, then just ambient air is blowing in. The fan never changes it's strength, it is just the heat that is no longer generated.

I'm sure there is a logical explanation that I am not seeing.
Help... winter is coming.

 

This might not be related to the quest, but my general knowledge tells me to:
1) check the level of coolant
2) check the heater control valve, as it is probably vacuum controlled. Check the lines to the valve as well.