HELP - Heat only when pressing the gas pedal

[vaak]

1993 Ford Ranger XLT 2WD Standard Cab 4 Cylinder 2.3L

As I have started to use the heat since we're entering the fall season, something strange is happening that hasn't happened in the past. When I turn the heater on, the only time I get heat is when I press the gas pedal (either stopped or driving). If I'm sitting idle, I don't get any heat. For example, if I drive somewhere, I'll have blasting hot heat the whole time I'm driving, but AS SOON AS I stop the truck and sit idling, the heat vanishes to cold air. I don't have A/C on my truck if that simplifies things. I'd like to get this corrected as soon as I can for warming up the truck in the winter and such. Any suggestions?

Thanks in advance...

Chad

[EVH5150]

My guess it would be a bad thermostat. My 92 ranger one time blew lukewarm air when I had the heater cranked. Changed the thermostat and started getting hot air again.

[stagefright13]

Happened to me in my Ranger and it was just low coolant level. Bad heater at idle.