low oil pressure lights up when idling

You could actually have low oil pressure but when you raise the rpm it goes up just enough to turn the light off. Your first step is to check with a mechanical gauge. If it's truly low some investigation is required. I hate to say it but this could be major. Stop driving the truck for now so you don't do any more damage. Use this link if you need to find a shop near you. https://repairpal.com/repair-shops Alex