How many miles should I expect out of plugs........... I hear some people say 15K miles; and my local mechanic tells me more like 7-8K miles or so. Just bought this 3rd gen, 68K miles. Runs great, except under full acceleration seems to "miss" alot; under light to moderate is smooth as silk.......... sound like plugs? Seems like if it was it would miss idling, moderate acceleration, etc. I'm wondering if it's a turbo issue? Thoughts? and thanks for the info......

 

and maybe while someones on the subject, how often should plugs be changed?

 

I change them every other oil change. Two months tops. How long do they last? No idea. I am extra careful, so I change my oil every 1500-2000 miles.

 

i change my plugs every 6 months...

 

If they get fowled. Usually yearly, which works out to about 10,000miles.

 

the more mods the more they need to get changed, especially for those of us who are running a little rich due to mods.

 

Depends on how you drive, also. Make sure you use the un-fouling pedal to the right of the brake pedal once in a while

 

Mazda specifies every 30k, my rotary shop tells me every 15k. I think every 7k is a bit excessive if it's stock. It all depends on the condition of your engine. When you pull it out, if it's sooty (rich) or burnt up dry (lean), you can change it. If it's barely used, don't bother wasting your money. NGK's are pretty darn expensive plugs at $8 a pop.

That's how I view engine oil. Some people change oil every 1500 miles. If it's still pretty golden, you are just draining money and polluting the environment, not to mention it's a waste of natural resource.