A method of and apparatus for starting and accelerating a vehicle through a range of vehicle speeds during which the vehicle internal combustion engine is operated in a plurality of different operating modes is disclosed. The engine may first be cranked in a compressionless mode preparatory to starting and then run in a second mode at a relatively low speed for a warm-up interval as a six-stroke cycle engine where each engine cylinder cycle includes an essentially adiabatic compression and expansion. The system may then convert to a third mode of operation as a four-stroke cycle engine during normal engine operation. Different operating modes are available during this normal operation. Under high demand conditions, the engine may be run as a conventional inefficient but effective throttled engine or converted to operation in a fourth mode as a two-stroke cycle engine. The vehicle management system includes a first read only memory for storing a fixed table of engine operating parameters corresponding to various engine conditions, and a random access second storage means for storing a table of engine operating parameters corresponding to various engine conditions with the second table being initially the same as the first table. The system responds to sensed engine conditions to modify the parameters in the second table and controls the vehicle in accordance with the parameters stored in the second table. Both short term modification to accommodate dynamic changes in the sensed engine conditions and long term modification to compensate for relatively slow changes in the engine and the management system are made to the information in the random access memory. The modifications may be on an overall engine basis or an individual cylinder basis.