Had acceleration lag for the last 20k miles (now 227k on odo)
Replaced plugs and if feels like new
Also MPG back to what it was as a youngster
(~30mph at 60mph)

Moral of story, don't take the 120k factory recommendation too literally

 

I believe, it is recommended to replace spark plugs every 100k miles or less what a coincidence!

 

lexus recommends 120k

 

Keep listening to Lexus recomendations because they care about their clients so much.

 

The 2007 Warranty and Services guide states 60,000 mile intervals for spark plug replacement:

 

 

My spark plugs have 85k on them and I am going to change them and the coil packs soon. Excited to see the difference it makes.

 

keep us posted on the difference

 

Unless plugs were seriously fouled and/or there were misfires, I don't believe there's going to be any real significant difference performance-wise. However, you may feel a difference in start up and smoothness. Either way, will be good to hear of your findings.

 

How many miles were on the plugs when you changed them? I can’t imagine it was 220,000, was it?

 

I don't think the Iridiums play that big of a difference when compared to copper plugs due to copper plugs having their gap widen. But yes there will be a slight difference. What will be bigger is cleaning your MAF, I jumped 3mpg on the highway after a maf clean, and smoother idle.

 

Original recommendation for the LS460 (and earlier models) was 100,000 miles. Then about 1/2 way through the 2007 model year, it changed to 60,00 miles "for emissions control warranty" (I had a 2007 before my 2014). I guess they were serious when the took on the "lowest maintenance cost of any manufacture" sales pitch!

 

Ditto on the MAF comment. Easily overlooked make a big difference..

 

had mine done at the dealer less then 2 years ago , big difference

i also got the valve springs changed through the recall so that could of helped too im not sure

 

is there a guide to clean the mass air flow sensor?