why does my car idle up and down when it is not in park when the fan is turned on?

Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. I'm sorry to hear you're having trouble with your vehicle. Your Outlander could be experiencing an issue with the idle air control valve (IAC) or the engine's vacuum system. When you take it out of park, the engine load changes, especially when you have the fan on and running the heat, which could be causing a fluctuation in idle speed. The cold weather could also affect how the engine responds, as colder temperatures can make issues with vacuum leaks or the IAC more noticeable. If the idle control valve is sticking or malfunctioning, it may not be able to regulate the engine's idle speed properly, especially under load when the fan is on. A vacuum leak could also cause similar symptoms, as the engine struggles to maintain the correct air/fuel mixture when the load changes. I would recommend consulting a trusted repair shop for a complete diagnosis. If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!