WHY DOES THIS TRUCK STALL

This type of issues requires a hands on inspection. Too many variable to guess at what's wrong with the car especially with very few details. If you have a check engine light on you can start by getting the car scanned for trouble codes. Most auto parts stores will do this for free. Report back with some codes but I suspect you are going to need to bring this in. Use this link to find a shop near you. https://repairpal.com/repair-shops Alex

3.3L V/6 ?