i have a 4cyl TE magna as a shitter. it's a single cam 4G thing.
anyway it's developed a misfire, none of the plugs looked any different so i put in a new set and took it for a drive for 20 mins & this was the result.
Any insights into general condition (plugs 1-3) and most particularly the reason that cyl 4 looks different.. fair to say that it's the one misfiring although i suppose it could always be all three of the other cylinders, just intermittently.
a little rough on idle & off idle, very light load (eg. take off down hill) it's fine but taking off on a flat bit or uphill, or any real load, it misses. high rpm free-rev it seems to clear out.