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LexusPro, ASE Master Certified
Category: Lexus
Satisfied Customers: 1303
Experience:  Lexus Master Certified, 11 yrs w/ Lexus Dealership, Elite of Lexus 2000-2011, 17yrs Auto Industry
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Lexus IS250: carbon build up

Customer Question

I saw that you had answered a question about carbon build up and piston repair on IS250. I have a 2007 IS250 with 43,000 miles and took it to dealership with check engine light and rough idle. I only have had the car for 1 year but it was regularly serviced at Lexus dealership before and after I got it. I was not low on oil, I don’t know if it got premium gas all of its life. The Dealership told me that it was carbon build up and already replaced my pistons but I am concerned that it may happen

again after warranty. They said it was a “permanent” fix. I would like to keep the car a long time but I have a few questions:

  1. I was told by others that I just need to do “injector service” once a year. Can I really avoid the problem again by doing injector service once a year or do I have to do soak procedure every year?

  2. Why is injector service or soak not recommended maintenance?

  3. Is my engine life expected to be shorter now that I have had carbon build up and they had to replace the pistons?



Submitted: 5 years ago.
Category: Lexus
Expert:  LexusPro replied 5 years ago.

LexusPro : Hello and Welcome to JustAnswer. I am reviewing your question and will be back with you in just a second.
LexusPro : That car has been plauged with misfire issues since it was introduced. First there was a bulletin for replacing valve springs. Then one for the top engine soak procedure. Now the newest for replacing the pistons and rings. Is it a permanant fix? Good question. 2010 models have the upgraded parts and I have heard of them also having the misfire issues. In my opinion the issue is caused by poor quality fuel and nonagressive driving. Cars that have agressive drivers seem not to develop this issue. Performing the top end cleaning works well if it is performed correctly. The injector service also helps. You can also manually shift into first gear and hold the gas to the floor and let the engine bump off of the rev limiter for about 5 seconds then shift to second gear. If there is carbon you will see a puff of black smoke from the exhaust.

What is "bump off the rev limiter" How do I know when that happens?


Do I need to do an engine soak once a year? how do I know when to do it so that I keep from damaging the pistons?


I am trying to decide if I should keep the car. Do you think my engine will have a shorter life or more problems since it has already happened to my car? Thanks, Lonnie

LexusPro : When you hold it in first gear the computer will limit the rpm of the engine, around 6500. I would only do the engine soak if it has misfires. As for shortened engine life, we haven't had enough time to tell. It is a known problem, Lexus will stich behind the repairs.

Thanks for your help, this is the kind of information I was looking for. Do I need to consider buying an extended warranty? If so, where should I get it from?

LexusPro and other Lexus Specialists are ready to help you
Customer: replied 5 years ago.

Thanks for your help, this is the kind of information I was looking for. Do I need to consider buying an extended warranty? If so, where should I get it from?

Expert:  LexusPro replied 5 years ago.
An extended warranty would not be a bad idea. If your car has navigation I have seen the screen fail often lately. A very expensive repair. If you buy a warranty make sure it covers that. I would talk with your dealer about warranty options.