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Old 08-02-2013, 11:19 AM   #18
BYprodriver
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Join Date: Oct 2008
Location: O.C. CA
Posts: 3,709
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Quote:
Originally Posted by woodsman View Post
Toyota will have that problem solved so fast nobody can do to Toyota's what Jake is doing to Porsche's! It reminds me of the book title- ENGINEER TO WIN!
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.
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