Are the 100k irdiums really good till 100k miles or should i swap before? i heard copper are better and just change more often?

Gap at .040?

46k miles now

 

nobody?

 

Depends on who you talk to. According to GM they are good to 100k unless in extreme operating conditions. Alot of guys change them sooner for various reasons.

 

I just changed my plugs for the first time at 110k and they looked great. I switched over to iridiums, but havent noticed any difference in performance or mileage. From what I understand you do not have to gap iridiums.