[woodsman]

Originally Posted by BYprodriver

Yeah, checkout the solution for 2006- 2009 IS250:

Hi guys and gals, I am a Lexus Senior Certified tech at a large Lexus dealership. In reading some of the posts here, I see alot of confusion about this subject. You seem to know about carbon build-up, but not the how or why and most important...the fix or prevention.
First, how and why...the misfire is caused when carbon that has built-up on the intake valve flakes off and becomes stuck between the valve and the seat causing loss of compression. This can last from a few seconds to minutes. It does not damage the engine, but can set a Check Engine light if it lasts long enough. The carbon is caused by crankcase blow-by...oil getting in the intake system. With a Direct Injection engine there is no fuel flow over the valve to clean it. The fix is to reduce blow-by...after you clean-up the valves. Lexus has another TSIB out for this. I believe it is L-SB-0068-11. It involes replacing ALL the pistons and rings,also cleaning the valves and replacing the valve stem seals. I personally have done 4 of these. It is most common around 60k miles, but have seen it as low as 29k. It is fully covered under 6/70 powertrain warranty. Now about prevention....I don't know of any. Why do some cars do it at 30k and others have 100k w/o a problem??? Synthetic oil may help, but not enough data to be sure. Good, clean oil can't hurt. The 350 and V-8 models do not have this problem. If you have any questions I will try to answer them as best I can.

can you find ONE more example? Just ONE more?