An oil product may soften the coke, but as soon as you start the engine, it too will coke as it has no where to go. Use a solvent product instead, like SeaFoam or kerosene.
An oil product may soften the coke, but as soon as you start the engine, it too will coke as it has no where to go. Use a solvent product instead, like SeaFoam or kerosene.