To identify a misfiring cylinder when a random fault is set (P0300), utilize the following; Select PCM (ECM) from the module menu (figure 1). At the top of the screen, mouse over ?Monitors? to open the drop down list. Select OBD II monitors. From the OBD II monitor list (figure 2), scroll down and select ?Which cylinder is misfiring?(figure 3). A value block displaying all cylinder misfire counts can be viewed and also monitored while running to isolate the causal cylinder. Once the specific cylinder(s) have been isolated, proceed with misfire diagnosis to determine root cause and repair as necessary.
