Spark Plug Keeps Gapping Itself
 

Hey guys, hope you've been well. Car just made 100K miles. My plugs finally shit the bed a month or two ago, so I replaced all of them and all of my ignition coils with OEM parts.

Last week I got cylinder 3 misfire. Like...completely dead. Had to tow the car. Swapped the coil into cylinder 1 to see if it was the plug or the coil - lo and behold, cylinder 1 started misfiring. So I figured, shitty coil, replaced it. Problem resolved, no biggy.

Now today, after a couple of boosts (Sprintex 210) I'm getting a cylinder 1 misfire. It only seems to happen at idle and low load. I have a replacement coil and plug - but I would really like to solve the root of the issue. Everything looks fine on my OSDB reader. Also I'll mention that my car hasn't pulled any timing, so I don't believe the issue to be knock-related.

Pulled the plug today and noticed that *again* the spark plug seems to have gapped itself. Should I just move to better plugs? This wasn't a problem for the first 100,000 miles on the same type of plug.


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Why is your electrode recessed so far into the plug? Is it loose at all?

I would bring that plug to your nearest service department (Subaru or Toyota, whoever you purchased the plugs from) and ask them how this happened.

That's not "gapping" a plug. Plugs are gapped by thousands of an inch. IE, small enough that you're sliding in spark plug gapping tools to measure it.

That looks like a straight up failed plug. The electrode is completely recessed into the rest of the plug and would never create a spark.

Right, I used "gapping" jokingly. I got the plugs from O'Reilly's. This is the second time this has happened. Been reading up on scam plugs recently - maybe whoever is supplying them had some BS plugs.

Hard to find anything else like this on the Internet...

Sent from my Pixel 7 using Tapatalk

Get plugs directly from the dealer or a trusted online vendor who sells the OEM part number. They are expensive but it's a critical part of the combustion cycle. Buy off brand windshield wipers and shift knobs, keep engine parts dealer part numbers whenever possible

So we can't even trust plugs from our local auto stores anymore? That blows!:sigh:

I have no reason to believe this is an issue with the plugs themselves. One could have been a bad plug. Multiples in a matter of a couple weeks is clearly pointing at something else.

Honestly since OP is on FI, there are probably knock events that are collapsing the plug, but I don't want to blame the tune until there is a known good sparker in the hole

There was. It failed too.

From my understanding, "my plugs shit the bed, so I replaced them" doesn't mean they failed in this manner.

It reads to me like he replaced 4 plugs that were worn out with 4 new plugs from the local parts store. Afterwards, this happened on, so he placed it again and is now here showing us the second auto parts store plug that has failed.

Am I just misunderstanding?

EDIT: YES, I did misunderstand part of this. He replaced a coil chasing a misfire. There's no information to support "I noticed the plug had gapped itself AGAIN", We don't know when this happened the first time, or if replacing all the plugs originally was because one of them had this happen