Re: Tappet noise, intermittent idle miss, rough shut-down
Clutching at straws with this guess, could you have a fault on a plug or cable and you can hear the spark? I had it once on a car, I saw the spark when it got dark. The spark had burnt a track on the cable, it looked like a firework display at night. Car seemed to run fine, which was the opposite of what I would have thought.
Maybe one or more of the plug covers are not on all the way.