This truck on the later trucks were getting into emissions the lpg system had a Asian lpg converter after a while the converter would gum up and when cold would stall or hard to start you probably need to replace it or rebuild it.as for the surge there is a step up value on the side of the carb that steps up the idel when you lift a load or turn the steering wheel to help so the motor does not stall out might need to adjust it hope l was of help.