Lexus told me 120K. I also read 60K. I know if you leave plugs too long it is not good, so maybe 90K?

I also read Denso TTs (IK20TT) for this car only last 30K. That is getting into copper territory.

 

owners service/maintenance manual calls for 60k mile intervals for the spark plugs.

 

Its like oil! The sooner you change it, the cleaner and more efficient it will perform. Sure you can push the plugs to about 100k miles and the car would probably run ok. But your mpg, over all performance of your car will gradually slow down.

 

The car looks like it was cared for, Lexus has a service history but at 90K the plugs weren't changed. Lexus said to see us in about 30k. I looked in the booklet that came with the car and it mentions 60k! Maybe because of the DI engine. I know a Corolla or Camry is a 120K interval.
I pulled a plug and the gap is moving toward .05. I think it could do a bit better in the idle quality and MPG dept. I get 16 short trip street only driving. Power seems fine but there is always room for improvement! Also planning on a TB cleaning. I cleaned the MAF and there is some improvement.

Still debating the OEM FK20HBR11 vs the IKBH20TT. They are long life plugs vs the thinner TTs. I read they only get 30k, in some cases though 100K, I have the TT in other cars and they are great. Ford uses a very thin finewire platnium plug and it is lasts 100k. I put the TTs in an older Explorer, I can tell a difference in power and idle quality. The plugs I replaced weren't old and went into another car. They are a great plug, but DI could be more wear and tear.

I am afraid to buy from Anywhere but Advance Auto (they are a Denso Dealer, on the site) because of counterfeits. They also have the best price.
Out the door with discounts and tax:
$32 for the IK
$83 for the FK

Rockauto is cheapest for the FK at 71.29 shipped. They use warehouses and Denso plugs are a big counterfeit item. Some fakes now are indistinguishable. Lexus said they had cars come back over fake plugs, even if done in a professional shop. They told me to buy from us or Advance. They said they use the IK if the customer has an issue with price but they aren't sure if it will last 120k. I see you can buy copper plugs too for $1 a plug :lol:. They may work better than the IR ones if you change them often. Copper is a great conductor.

 

Rockauto is a trusted source, 71 bucks is a good deal for FK plugs. I used FK plugs on my car and paid a premium just to ensure they're legit.

 

2006 GS 430, 155k miles, original plugs. Car drives great, pulls hard and gets a combined 23 mpg in city/highway. Should i be looking to change the plugs? What's the worst that could happen if i don't?

 

 

 

 

It is like the guys with 50K mile oil changes. Sometimes you get away with it, sometimes not. A misfire can destroy a cat very quickly. I know on some engines plugs can seize in, I don't think so on these if they have 120K intervals.

 

never have understood the mentality of delaying cheap maintenance. Oil changes, plugs, filters, fluid changes, coolant changes, etc....are ALL cheap. In fact, VERY CHEAP in comparison with having a failure fixed by a Lexus shop. If the book says change ANY of those items at a recommended interval, then just do it. Why push it plug to 120k freaking miles when they are less than the cost of a decent meal out?!!

 

I have to agree with this. You CAN prolong routine maintenance, but is it really worth it? Personally, I do plugs every 60k, transmission fluid every 50k, air filter every 10-15k (spray with canned air every few months + wipe the air box clean), coolant every 30k, oil every 5k, and diff fluid every 30k. Some say it's unnecessary, but I figure why not? I don't plan on buying a new car anytime soon, so better keep on top of the basics.

 

 

I just picked up a 2008 gs 350 3 weeks ago already have a new air filter,changed the oil and plan on doing the plugs I got it from a Toyota dealer with 123,xxx on the clock.i figured it should be broken in now.,lol excellent non smoker 1 car owner.just gotta figure if I can do the plugs or just take it to Toyota.the Supra was so much easier...
edit,just saw a video on it,it should be aasy!