I will need to lookup what method this engine uses to trigger coil firing… Usually its an electronic sensor bolted into where the Ole Distributor used to be…this being on engines that were alive in the distributor days and have been updated over the yrs to more modern methods. This vehicle doesnt have the sensors or complexity to single out just one cylinder…so it reports as best it can In this engine…with its single block coil pack…firing 2 at a time…how can it be super accurate when it knows it didnt fire one set of plugs? Or at least thats how Im thinking about it. Depending upon the complexity of the ecu software or code…will dictate what kind of report accuracy it can reveal. LOL… In that Audi example…you would never recieve just one misfire report…always grouped in twos. My buddy keeps a spare in the trunk on an otherwise troublefree car. 99 Audi A6 2.8 V6’s do this and those coil packs are like socks…you basically need to change them daily…Those coil packs fail like no ones business. On many 4 cylinders this is the case…you will see 1 and 3… and 2 and 4 fire simultaneously which is why it is called wasted spark. I think this engine still uses the wasted spark technique…firing plugs in groups of two. When you fire them in groups you can get wonky report cards. Now in a coil over plug system where everyone has their own coil…you will receive a much more accurate report card. The delay or offset time in firing one plug or group of plugs will appear as a single cylinder misfire if it is timed just right…the ecu basically reports on just one of them…. However ASEmaster is also correct stating that it cannot cause a single cyl misfire…but…when you mis your ignition window…and you are a spark plug in a cylinder. Like Rod Knox asked in his question… Can a faulty cam sensor fire a coil pack out of time… The answer is yes as its timing is dependent upon cam chain stretch usually.
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