1. An engine controller suitable for use with an internal combustion engine having a plurality of cylinders, each cylinder
having an associated piston and being arranged to operate in a succession of working cycles having at least four strokes,
the engine controller comprising:
a skip fire controller arranged to direct operation of the engine in a skip fire mode that causes selected active working
cycles to be fired and selected skipped working cycles not to be fired, the skip fire controller being arranged to make firing
decisions, wherein the firing decisions are made on a working cycle by working cycle basis; and
wherein the engine controller is arranged to deactivate skipped working chambers during selected skipped working cycles to
thereby prevent pumping air through the skipped working chambers during the selected skipped working cycles.