Q: Truck shuts off when i stop before I hit the brake pedal but idles just fine. What can cause that to happen?

Hello. Engine stalling can be caused by many things. A few common causes are issues with the fuel, ignition, or engine management systems. If any of the components to one or more of these systems fails or has an issue it could cause the engine to experience performance problems and stalling. Any issues present would be magnified by cold weather, as cold conditions require more fuel and tuning adjustments for smooth engine operation. A few things to look at would be the spark plug wires, the ignition coil, the idle air control valve, and the crank position sensor. A fault with any of these components can all cause stalling, as well as other performance issues. If the stalling appears to be related to your pressing on the brakes then it may be possible that there is some sort of vacuum leak, or an issue with the brake booster. As the possibilities could be many, I would recommend having a professional technician, such as one from YourMechanic, come to your location to diagnose what may be causing your stalling.