Sugar In The Gas Tank Doesn't Really Work

[ProfessorGAC]

I suppose your "few pounds" could clog a fuel filter, but since it's completely insoluble in gasoline, it just sits in the bottom of the tank
If it gets to the engine, it will burn just like the gas, albeit releasing only around 40% of the energy per unit mass.
Sugar in the gas tank is mostly an urban myth.
Now, concentrated sulfuric acid is another story, but much more dangerous to mess with than sugar.