Abstract: A method for detecting a source of a misfire for an engine having turbulent jet ignition (TJI) during a service routine is presented. A diagnostic tool is coupled to an engine controller of the TJI engine. An increase in revolutions per minute (RPM) of the TJI engine is commanded. An engine roughness is measured and a baseline engine roughness for the TJI engine while all cylinders are in an active state is established. A first main spark plug is commanded to deactivate. A first test engine roughness of the TJI engine is measured based on the first main spark plug being deactivated. The baseline engine roughness is compared to the first test engine roughness. A determination is made, based on the comparison, whether the first pre-chamber is fouled.

Abstract: A skip shift device performance detecting method used to more accurately enable skip shift diagnostic execution in a manual transmission equipped vehicle where a skip shift has been requested and a transmission clutch remains engaged. Where a skip shift request ceases during clutch engagement, a timed loop is used to monitor if clutch disengagement occurs before the loop times out. Where clutch disengagement occurs before the loop times out, skip shift diagnostic execution is enabled. Where the loop times out before disengagement, skip shift diagnostic execution is disabled. Where the skip shift is requested and the clutch remains engaged, the skip shift request is monitored to determine whether it is withdrawn before clutch disengagement. If it is withdrawn before clutch disengagement, the aforementioned timed monitoring loop is executed. If it is not withdrawn before clutch disengagement, execution of the skip shift diagnostic is enabled.

Abstract: A skip shift device performance detecting method used to more accurately enable skip shift diagnostic execution in a manual transmission equipped vehicle where a skip shift has been requested and a transmission clutch remains engaged. Where a skip shift request ceases during clutch engagement, a timed loop is used to monitor if clutch disengagement occurs before the loop times out. Where clutch disengagement occurs before the loop times out, skip shift diagnostic execution is enabled. Where the loop times out before disengagement, skip shift diagnostic execution is disabled. Where the skip shift is requested and the clutch remains engaged, the skip shift request is monitored to determine whether it is withdrawn before clutch disengagement. If it is withdrawn before clutch disengagement, the aforementioned timed monitoring loop is executed. If it is not withdrawn before clutch disengagement, execution of the skip shift diagnostic is enabled.