Résumé : 1 The introduction of OBDII and EOBD involves misfiring detection, a critical issue for engine management systems. The paper reviews the multiple sources of misfiring, and presents an overview of the different detection methods. Moreover, misfiring detection experiments, based on instantaneous engine torque measurement, were performed at the Brussels University, in collaboration with Mannesmann VDO, highlighting the difficulty to develop a reliable detection method. Copyright © 2000 Society of Automotive Engineers, Inc.