Issue: 2005 Xterra heater issue

[Encryptshun]

Hey all. I've tried to track this down via the internet, but I haven't found anything yet. Figured I'd try you all before I blindly turned it over to a mechanic.

Starting about 2 months ago, my Xterra's heater starting acting funny. Even when warm, it will blow out cool or cold air when at idle or less than about 1500 RPM OCCASIONALLY. It doesn't seem to matter how cold it is outside or how long it's been warming up (though it definitely happens more when it's below 30 deg farenheit outside). Other than driving on the highway or otherwise keeping the revs up, sometimes it seems that moving the knob from floor to defrost and back will fix the issue temporarily.

I first figured it was a vacuum leak, but if that was the case, wouldn't it happen all the time?

I'm out of ideas. HELP
Modified by Encryptshun at 7:50 PM 2/12/2010

[RT22]

sounds like the doors that activate which vent is open is messed up maybe letting the outside air in , as in the vent or recirculate portion is messing up. or the flow to heater core is being mostly blocked and when idling there is not enough warm water across the heater core to keep warming the truck.

[Encryptshun]

sounds like the doors that activate which vent is open is messed up maybe letting the outside air in , as in the vent or recirculate portion is messing up. or the flow to heater core is being mostly blocked and when idling there is not enough warm water across the heater core to keep warming the truck.

So do you know what I should be looking for to find out if either of those is the case? Is that vent vacuum-actuated or electronic?

[pejsa s-13]

pull the heater core and clean it out and take your compressor and blow through all your heater lines?