98 Montana 3.4 ltr- heater colder at idle?

[jaso1108]

Seeing if anyone has any input on this- our Montana seems to blow colder (I would say much colder, not just a little) air when at a lower idle speed. It's not a dual system at all- just a front heater/AC.

The coolant level seems fine, and the engine temperature is spot on- not sure what else to check? I've heard somewhere that there is a part that fixes this, but I'm not sure what it is?

Thanks,

Jason