Like title says I have a 2004 2.7l v6 with 133k on it. It is cold out now here in MN, when I use the auto start, the heat doesn't get warm because it is idling at or below 1k. when sitting in it running it does the same. If i rev it up the heat kicks in right away. Any Ideas as to what it may be? Heater core? Radiator flush?

 

that would be my guess clogged heater core ,hose or radiator, possibly weak water pump ,the heater core is a 6 or 7 hour job ,if you can get hoses off might be able to run from a garden hose thru hoses,

 

Update: opened radiator overflow cap for five minutes while running, noticed was low on coolant, added to full cold and Voila...I have good heat again!