I was driving around today, stopped at a stop light and the car died. I tried starting it but nothing, it just cranked and cranked. I gave it a good 20 seconds and tried again, the light was still red, this time it started but it immediately died again.

I finally got it going by keeping the RPM's up, luckily I was a block or so from my house so once I got home I checked to see if there were any pending codes as there were no active CEL's. Nothing popped up?

I was stumped so I pulled the plugs and low and behold my rear leading spark plug was missing half of the ceramic insulator!!

I went out and got a new plug and put it in, car started up fine, no issues!

TLDR;

My question is what the hell happened?!

The plugs had about 15k miles on them, and when I first installed it, there was no visible defect. Still no codes have been thrown and the car runs fine again, no stalling.

 

any number of things, we used to have that happen at the dealership, and it turned out that on average the spark plugs were at the top of the daily stock order, so they were the first thing that got tossed into the box to go on the shelf, the toss would break the plugs...

i've seen them do this with really high mileage too, but it was like 50K or something.

detonation will also do it too, but if you have a stock car that is probably less likely than the parts guy dropping the box....