[Heihetech]

There are many posts talking about "misfire" caused by DCD. As I have said
before, this is not true misfire due to missed or abnormal burning. Under DCD
control, normal combustion still happens in the cylinder. When the cylinder is
deactivated, there's totally no fuel injected, thus totally no firing but some
mechanical irregularity will happen, let ECU find a "misfire". This is very unfair
to DCD. It's true misfire can cause mechanical irregularity, but mechanical
irregularity during DCD will never mean chemical misfire. So, OBD-II should
better use other way to detect misfire, such as combustion pressure, or gas
expansion by knock sensor. Therefore, OBD-II software must be modified
accordingly, give the way to DCD operation. We all know OBD-II is the law,
but the law is man-made, and could be revised as required. Detecting misfire
by mechanical irregularity has been out-dated, at least not so perfect.