Sorry but Mythbusters have tested it already, the sugar made it run better.... These are the Myths from that epasode -
A car engine will be destroyed when liquid drain cleaner is put into the fuel tank.
busted
The engine still ran.
A car engine will be destroyed when bleach is put into the fuel tank.
plausible
The engine soon died out but wasn’t ruined from the experience. The following morning, the inside of the gas tank was covered in rust.
A car engine will be destroyed when sugar is put into the fuel tank.
busted
The engine ran even better than without the sugar.
Adding mothballs to the fuel tank of a car will increase its horsepower.
plausible
The engine still started, but it soon started spluttering. When Jamie pressed the accelerator, the engine sounded more powerful.
When a car radiator is bone dry, cola can be used as a substitute for coolant.
plausible
The car ran with cola in the radiator, but it may cause damage.
When there is a leak in a car radiator, cracking an egg into the radiator will plug the hole.
plausible
The engine was started after the contents of an egg were poured in, and the leak stopped.
A piece of metal can destroy a car engine when it falls in the carburetor.
busted
A penny dropped in could be heard rattling, but the engine still ran.
Adding bleach to the oil of a car can destroy the engine.
confirmed
The engine started but it soon started smoking, and very quickly overheated. The engine was so hot, that the undercarriage started burning and Adam fried an egg on the tailpipe. The engine was ultimately ruined.