That's what is seemed liked based on the limited research i did do, but i just wanted to make sure. Thanks Jsolo.

 

This is how my plugs looked at 123,000 on my 2008 G37 coupe the job took 2 hours I also cleaned out the Throttlebody both sides they where dirty. I'm good for another 100,000 miles my car is running like a champ.

 

This is how it looked close up

 

Just changed mines as well at 61k miles.

 

Here's is the spark torque speck

 

So they gained 15 hp by changing their plugs? I'd like to see that. Also how many miles did they have on their car when they changed them?

 

My car is reaching 100k soon. I need to start changing my plugs and tranny Oil soon too. Thanks for diy

 

Auto or manual?

 

I'll be doing this very soon as I've got around 105k. Knock on wood. Luckily I don't have any issues. Not really looking forward to taking off the throttle bodies (just more to screw up) but it beats paying the dealer $300-$400. Thanks to the OP for the write up though.

 

uh... i just check't 2 weeks ago and both my G37 came with NGK iridium spark plugs as OEM... They luck like new even after being used for 5 years...

 

Just changed my plugs. I'll post pics of the plugs later, but with 105k miles they look like I could have gone another 100k. Not bad at all.

 

You will never convince me plugs are good for 100k miles. My Xterra (4.0 VQ) started declining gas mileage after 60K but I didn't get to the plugs until after 100K and went from ~16.5 mpg to ~19.5 mpg. Nothing else was done at that time. I still think the plugs started to fail after 50K miles. This is on my list of things to do as I'm approaching 60K. I'm not saying you would see this type of improvement but it was obvious the plugs made a huge difference in MPG. Not sure about power, didn't drive it very fast.


Has anyone tried running copper plugs? I used to run them in my Maxima and they were great. They don't last long, but are cheap. I used to change them every year/year 1/2 (probably major overkill) and cost me about $12 and 45 mins.

 

Yeah but what kind of plugs were you using on the Xterra? Platinum? They are usually rated for around 60k I believe.

Our factory Iridium plugs are rated, at least from what I've read/seen, for over 100k (105k maybe?).

 

Decided to replace my plugs yesterday and upon pulling out the coil pack on the first cylinder/chamber, I noticed some oil in and around my spark plug. Mind you, I replaced my plugs at 50k and now just replaced them at 125k. On that note, my G was experiencing the dreaded, throttle lag, which could have had something to do with a plug that was soaked in oil.....Anyway, only one cylinder had oil in it, but that particular plug unscrewed very, easily versus the rest of them needed some force to remove.

Ultimately, the amount of oil in the cylinder that accumulated within 75k miles was pretty minimal, so Im not concerned about it. End result - My G feels amazing! Idles smoother, low end torque has returned and it much more responsive regarding throttle

 

Interesting. Any pictures? I'll be replacing mine tomorrow. This diy makes it look so easy lol