Abstract: A system and method of disabling at least one cylinder in a multiple cylinder combustion engine is disclosed wherein the fuel combustion air intake valve is closed such that essentially no fuel enters the cylinder, and the exhaust valve is opened such that the piston can move essentially unimpeded. This is accomplished by disabling the rocker arms associated with each cylinder valve, preferably by a pair of auxiliary cams which can be computer controlled, or be operated by the driver. Additionally, a circuit for disabling power to a cylinder or engine while maintaining power to other operational loads is disclosed.