I remember one of the automakers had problems getting the OBD-II mandated misfire detection working properly with a manual transmission, so they didn't offer it for one year.
Misfire detection usually works by sensing the deceleration of the crankshaft as the misfiring cylinder misfires--apparently rough road caused false misfire detects on manual transmission equipped vehicles. I don't know how they resolved this problem, as they obviously did.
Of course, the way GM does misfire detection on the Ecotec engines is totally immune to that problem since it actually measures the resistance of the ion path between the sparkplug electrodes to determine if a misfire event occured.
Misfire detection usually works by sensing the deceleration of the crankshaft as the misfiring cylinder misfires--apparently rough road caused false misfire detects on manual transmission equipped vehicles. I don't know how they resolved this problem, as they obviously did.
Of course, the way GM does misfire detection on the Ecotec engines is totally immune to that problem since it actually measures the resistance of the ion path between the sparkplug electrodes to determine if a misfire event occured.