Replacing spark plugs at 116k miles. replaced 6 plugs so far.
The gaps for 4 out of 6 plugs are almost the same as the gap of a new one.
2 out of the 6 plugs show increased gap. as shown in photo.

 

I have an 07 LS400 and it now has over 140,000 miles on it.

A couple of months ago I asked my mechanic to change the plugs not knowing when last changed.

He said the plugs are original, now over 15 years old.

My car still started and seems to run just fine, but now with new plugs I can tell a definite positive difference.

 

I changed the plugs on my 2013 at about 60k miles. They could have gone to 120k easily. It seems that the pre '13 engines wear plugs much quicker. As pointed out, the engines still run well enough, even when past due.

 

Here are mine I changed out last week. I recently bought the car and had no records of when or if they had ever been changed. 120K miles. They were pretty crusty, but consistent. They could be original. Someone posted that there are markings on the plugs if they are original, but I couldn't find any.

 

My car has 161K and while looking at all the maint. records, I didn't see any plug changes. I drive 75 miles everyday on the highway, (At 85 MPH) and I still get 28 MPG. I keep debating if I should change the plugs or keep waiting. If it ain't broke.......Hmmmm

 

Change them before you erode them too far, the reason it has those side straps is to "catch" a failure to fire if the main strap erodes too far and it hides any issues very well.

 

I'm thinking that they were changed before I bought the car. I git it when it had 120k.

 

I have a new set and the seals ready to do the job.

 

"git"??? Is this a NC thing?

 

Definitely change them.

 

Typing too fast.

 

Update on the effects of tune up (new spark plugs, cleaned throttle body & MAF sensors)

Now the LS460 runs very smooth, idles with almost no vibration, can not tell if the engine is running.
highway cruise at 70 mph I got 32 MPG, with tire pressure 36 psi.
before the tune up i normally get maybe 28 MPG on highway.
Definitely worth it to replace the spark plugs.

 

Did you replace the plugs yourself?

 

yes i did.

 

Did you have to remove the battery tray? How long did it take you? I was watching the Formula 1 race the other day and I saw them change 4 tires and fill up the gas tank in 2.7 seconds. How good did you do?