CPB

Yep, replaced mine at 15k, the ACDelco plugs are all over the place with quality. You can test them with an ohmeter and see a massive swing in resistance levels. I replaced with a quality iridium (NGK or Denso) and the misfiring is gone.

CRS1962

Might still run but plugs have lost a lot. I change for sure them by 70k 100k is too far for sure.

CRS1962

I do and if you do you will figure out they do run better with fresh plugs. After 60k they go on the list to do! Change them and never run them out to 100k.
That is my take. Million mile plus driver here.

joemessman

I was taking about my Z06. It's every 60K. I also have a Stingray and it is every 120K

Midnight_rider

You used copper plugs for a year? I used to run copper plugs on my Evo and that needed replacemrnt every oil change at 3k miles. They foul insanely easy.

aklim

I used to on my modified C4. Probably put 10K plus on it every year.

Rich427

I just saw this post today. I have a 2014 convertible, 7 speed that I bought new in November of 2013. It only has 16k miles on it. I am retired, have more than 1 Corvette, and they get driven regularly, just not long distances very often. Lately, I have noticed at idle I will occasionally get a little stumble or miss. Rev the engine a bit and it smooths out. I was starting to wonder whether I had a fouled plug, or bad plug or wire. So, thanks for this post. Even though it only has 16k miles, with the heat in SW Florida, maybe its time for new plugs and wires.

Midnight_rider

you can try the plugs first. I think the wires are solid.

aklim

I am kinda mixed. On the one hand, I would think that for a couple hundred bucks, I can do it while I am already there with the plugs, there is the other end that makes me unsure if the wires are good. IOW, now you have a new variable and we can't be sure the plug wires are 100% good. Maybe check if there are misfire codes and try swap wires around first?