Can't find a thread on this issue. Sorry if one exists and I missed it.

Question:

How often--in terms of months/years or mileage-- would you expect plugs to perform well? I'm now on third set. Odometer at 35,000.

Thanks for your help.

 

If you are stock 35K, but we have seen them go much further on a good tune and all hi-way. The problem is you don't want to take a chance and have one fall apart into an engine....If it gets flooded you might need to change them earlier.

 

Well, standard copper plugs are said to last anywhere from 10,000 to 20,000 miles (16,093 to 32,187 kilometers), while more expensive iridium or platinum spark plugs can last 60,000 miles (96,561 kilometers) or more. Some high-end iridium plugs are advertised to go more than 120,000 miles (193,121 kilometers), but there's no actual guarantee they'll be able to achieve this.

 

My OEM ones lasted 72k. my service advisor was shocked and told me they were supposed to be changed every 30k

 

Stick with the OEM NGK plugs.

 

on this car... i'm fine with not leaving anything to chance and change at the recommended interval, or sooner.

the originals that came with the 8, was replaced at 25k when i inspected it due to intermittent misfire. sure enough,the insulator on one had a hair line split by the electrode...

imagine if i didn't catch that, and the ceramic insulator dislodged into the housing, with just less than 25k on the car. i'd be one pissed off 8 owner, and a member of the new engine club, on a new car!

 

These were my stock plugs after 35,000 miles.



At 25-30k I'd start pulling them to check their condition.

 

20.000 miles of normal use with properly working coils. They're a cheap maintenance item so there's no need to be stingy!

 

I don't believe your left plug was firring....... did you replace the coil or wire?

 

That looks bad...

 

Im at 67K on OEM Plugs and Coils.

 

No. I had a CEL for a misfire and replaced the plugs. It went away. Everything runs fine now and I've checked the plugs (5k miles later) and they look normal.

FWIW the other rotor's plugs looked pretty much the same.

 

Your on par with me

I change mine every 15K and coils every 30K even if there still in good shape, cuz I'm crazy like that.

Mazda say's to change plugs every 30K, but we all know that the life of mechanical parts can very from car to car.