Can anyone help? My 03 accord 2.4 lt. interior heater only kiks in at 2000 rpm. otherwise it just blows cold air at idle. Thanks ahead for any replies!

 

Sounds like a bad heater core. Unless you can live with intermittent heat or do it yourself say goodbye to about $1000.

 

There are a lot of possibilities. If your coolant is full and your not seeing the temp reading staying low, then you can rule out a thermostat issue. I've seen the hot/cold actuator not working correctly keeping it from going to the full hot setting as well.

 

Check your heater valve as well it maybe partially stuck, so when it flows slowly (idle) it doesn't heat very well but when the water pump pushes it thru it gets warm. Could be low on coolant or possible plugged heater core.