How long should NGK Iridium plugs last?

I put a set of NGK Iridium plugs Part number 6510 in my dude at 135K when I put my S3 on. I am now at 150K (so about 15K on that turbo/plugs and about 5k on corn). I am starting to get an intermittent miss here and there but no check engine light yet. I pulled my plugs today and they look ok'ish. All 4 of them had opened up their gap about 3-5 thou so I re-gapped them back down to .024 (as recommended by freaktune during my tune sessions).

Reading online says these plugs should last 50k. But I am wondering if boost and/or corn are shortening their life? Anyone else getting good life out of their NGKs? I ordered a used coil pack to keep on hand in case I finally do get a CEL... Thoughts?

 

Post pictures. If the ganhad opened that's your issue as long as the plug itself looks fine keep running them

 

I don't know of anyone that gets 50k miles out of their plugs I usually swap mine around 18k or less

 

Copy. I can't pull them for pics for about a month and a half. It does seem to be running much better now that I re-gapped them, though. I am road tripping from SoCal to Boise next week (via Mojave) so I am trying to make sure it is all ready for the drive. Just bought a spare OEM coil pack I will throw into the glovebox for the drive.

Maybe I'll swap the plugs next month when my move is complete.

Unrelated: There are no E85 stations between here and Boise (annoyed) so I will be driving up on 91 octane after the first tank dries up.

 

I've changed mine at 50k freedom units twice and felt like it was a waste of money both times

Iridium is supposed to be good for 100k miles

 

Well I'm glad I know someone now that does, do you re gap in there?

 

Only once when I had a gap open way up after about 15kmiles. Checked all four just the one was opened. Honestly the electrode had the exact same shape as the new ones no wear

 

Interesting very interesting I may take a better look at my set before replacing them next time now

 

I'm admittedly very cheap about spark plugs. My first car started using a shitload of oil and would tend to foul the plugs every 4k miles or so, being in highschool I didn't want to keep buying plugs so as long as the electrode wasn't eroded I was cleaning the crud off them checking the gap and running them again. With that experience I tend to really look at the old plugs when I pull them.

I have an old set for the ms3 in my garage that looked good when I pulled them. I'm out of town but if I remember when I get home I will see if I can find them and post a picture of them for reference on 50 k plugs.