What is carbon deposit in a vehicle?
It is accumulation of dried up fuel at the injection valve and wall of engine cylinder. It will grow bigger as it absorbs the incoming fuel.
Carbon deposit could cause lesser air and fuel go into the cylinder. This will result in incomplete combustion, lower compression ratio and power.
One way to clean up the carbon deposit is to use diesel additive or petrol additive. It serves as a detergent to keep the fuel injector clean. It can slowly clean up the carbon deposit by breaking the bond between carbon deposit and the engine parts.
For more information on diesel and petrol additive, please refer to http://www.powerzone-biodiesel.com.