Fake plugs? Unlikely although not impossible.
What I DO know is this............see the pic of the new plug above and the small iridium extension that comes on the WIRE electrode, or the one sticking way out in the air. Those super small tips are barely spot welded on and can be a crap job doing it. I've begun to closely inspect all plugs with tips like that, some are missing right out of the box and others can fall off in operation and then the gap opens up super wide. You also look for the tips missing when plugs get pulled out at inspection. The engine then begins to misfire OR if the coil is powerful enough and can fire even that wide a gap then it burns the plugs' other tip off due to being too hot. Coils auto increase voltage to jump gap and the more powerful the spark the more material vaporizes off the end the spark jumps away from, meaning the center one.
If you look at the used plugs there the wire tips likely came off, bad welds. Then the centers burned the tips off as those are not the 'tee' shaped weld on buttons like the other side, the center is often a bigger diameter with the end turned down to make the small tip, at least so far. I suppose they could weld a tip there as well to save more money, iridium is not cheap. Maybe they do but the weld there is better, I don't know. But you can see the bottom base of the tee on those so the entire tip did not come loose. Think of the wire end shape there as like a steel rivet like Bluto throws buckets of at Popeye in the cartoons.
As mentioned above name brand parts are made in so many places now you cannot grasp where they come from, the crap weld job on the tips can be the worker simply dropping amps on the welder to save the company money on power. Or sloppy machine holding of the tips to not locate or feed the tips precisely or even drop them to weld with no tip in place. Look at the parts out of the boxes, you'll see all kinds of errors there. The physical process of gap setting can have some of the tips come right off, BTDT. I've even found loose tips in the boxes.
Misfire codes are usually electrical related as the ECM can commonly see the error in voltage there and in more than one way, but sometimes they can be due to like a vacuum leak. Always treat ignition electrical issues first with that code.
Last edited by amc49; 02-24-2019 at 07:23 AM.