When i have my heat turned on the car shudders while driving. If im idling it will turn off. The heat is blowing out hot though like it should, im just worried that its going to mess up my car.
When the engine is idling, what will turn off? .The engine, or, the blower ? .The heat blower motor is electric. It could be causing too much of an electrical load on the electric supply system (alternator/battery). Checking the amperage draw of the blower motor will reveal how much it’s loading. There could be a problem with the wiring circuitry, or the blower motor, itself. Also, the alternator/battery carrying capacity could be sub-par. Have those checked at many auto parts stores, in the car.
I doubt the heat alone could put that much load on the engine (it would just blow a fuse). Do you have a climate control system that automatically turns on the AC to dehumidify the air? My best guess is that the AC compressor is putting a load on the engine and causing it to idle too low and/or stall. What make/model are we talking about?