Dec 16, 2014, 12:59 PM
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IS250 Engine misfire-explained
Its not a total solution but it helps a ton. I installed one on my sisters car after I cleaned the top of her valves myself and installed the catch can system. after that she has not experienced any issues and my dad drains the can at every oil change and it picked up a lot of oil that would otherwise be ingested back into the intake manifold.
i had my piston and rings replaced last year but took a lot of work between calling corp office to only have them tell me nothing can be done but after speaking to them several times and stating im not making this up they said they were able to "take photo's and saw there was a bunch of build up" only problem i have is what do i do when this comes back and nothing is covered.......
great question as this has came back on my car
Lexus Test Driver
Joined: Mar 2008
Posts: 9,994
Likes: 247
From: California
Just an update and FYI for others: It's been 3.5 months since I had the pistons/engine done per warranty. So far I have not had one near-stalling episode while at a stop. Just a continual slight rough idle just before I come to a stop. I will accept this as..... acceptable.
Lexus Test Driver
Joined: Mar 2008
Posts: 9,994
Likes: 247
From: California
Rookie
Joined: Sep 2014
Posts: 87
Likes: 0
From: Indiana
Let's say I bought an '07 IS250 AWD from a non Lexus dealer. Is this still covered under that 9 year unlimited mileage deal or do you have to have a CPO or Warranty through Lexus? Car is currently at 74,3XX miles and just experienced a stumble/rough idle at a stop light tonight.
Driver
Joined: May 2013
Posts: 135
Likes: 3
From: Bay Area
I bought my car used w/ 69k (have about 96k now). Never took it into lexus for anything till a yesterday for a couple recalls (no warranty). My SA said he's been getting a lot of is250's coming in with the issue and would run the diganoistic for free. They recorded some misfires while they tested for the tsib. Anyway waiting to see if Corp will approve it tomorrow.
Lexus Test Driver
Joined: Apr 2013
Posts: 815
Likes: 0
From: Florida
Let's say I bought an '07 IS250 AWD from a non Lexus dealer. Is this still covered under that 9 year unlimited mileage deal or do you have to have a CPO or Warranty through Lexus? Car is currently at 74,3XX miles and just experienced a stumble/rough idle at a stop light tonight.
Driver School Candidate
Joined: Jan 2016
Posts: 12
Likes: 0
From: Pennsylvania
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-0048-11. 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.
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-0048-11. 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.
Driver
Joined: Nov 2016
Posts: 50
Likes: 1
From: Ontario
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-0048-11. 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.
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-0048-11. 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.
hey I’ve been having some problems with my IS250. Could you please check my thread and suggest something? https://www.clublexus.com/forums/is-...l#post10232339
Lexus Test Driver
Joined: Mar 2008
Posts: 9,994
Likes: 247
From: California
I've had the rough idle twice now since having the recall done. It's not as harsh as before, and I don't see the tach moving down at all. It's just a rougher idle for a short period while stopped. I will bring it up to the dealer again. Doesn't bother me if it only happens once in a long while and the car does not actually stall.
Driver School Candidate
Joined: Jan 2022
Posts: 1
Likes: 0
From: California
Misfire cyl 2 & 4
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-0048-11. 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.
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-0048-11. 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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