PURPOSE: To prevent reccurrence of engine stall effectively, in an electronic controller for car engine, by storing the operating state of engine as time sequential pattern data and reflecting the results onto engine control or diagnosis.

CONSTITUTION: An electronic engine controller is provided with various sensor group 20, operating means 21, actuators and display means 22. While an actual operating pattern measuring means 20 will sample/store the operating signals from sensor group 20 with predetermined period. An acutal state deciding means 24 with dicide that the engine has entered into specific state from the outputs of sensor group 20. Furthermore, state operation pattern memory means 25 will store the level stored in measuring means 23 when said means 24 has decide that the engine is in specific state as the operating pattern data corresponding with said specific engine state. The operating means 21 will perform operation on the basis of outputs from memory means 25 and operating signal from sensor group 20 thus to function actuators and display.