G35 maintenance guide for all schedules goes up to 120,000 miles. Not once do they say to replace plugs. Is this right or am I missing it? I realize they are irridium tipped plugs but still, I imagine they would need to be replaced at some point.

If this question has already been addressed, sorry. I did search for it first but did not find anything.

Thanks.

 

The plugs will last to 105k. (Page 39 of the guide). Depending on engine condition and driving habits you may need to replace it earlier. I had Platinum-tipped plugs in my old car that looked just fine at 110k when i replaced it.

 

soundmike,
Thanks for reply. I just checked my 2008 Infiniti Service and Maintenance Guide and that line (replace spark plugs) is missing from my 105,000 recommended service. Must've been a glitch they caught and fixed for 2009 MY.

 

That's funny. I guess they figured the plugs don't last that long, or that people will be upgrading soon before it needs replacement.

Generally speaking, 105k is fine. You can certainly replace it before, i'm planning on doing mine at 60k. (mainly to see how it's doing, but since i'm already on it, might as well replace the plugs)