Originally Posted by RandyIS250

I believe you because u said 3 out of 1 get carbon build ups, more or less all will have these problem, i wanted IS350 but somehow end up with IS250, my brother said drive it for 2 years and get rid of it.

Originally Posted by azari

Leg3ndary,

I think the fact that your car's diagnosis for carbon build up came back negative is pretty promising for us 2010 and newer IS250 owners. A rough idle can be caused by a number of factors. So far I haven't seen any diagnosed cases of carbon build up with the 2010 (modified pistons) and newer cars; at least not yet! Mine is a 2011 with over 80k miles and runs great. Hopefully it'll stay that way!

Originally Posted by Jeff Lange

Not like in the IS250 or other cars that use direct injection.



This agree with to an extent. It seems like whenever someone with an IS250 has any rough running issue, it's immediately assumed to be carbon build-up, when in fact there are many issues that can cause rough running. That's why diagnostics are important to verify the actual cause of the issue. The one nice thing about the IS250 is that it has almost no vacuum lines.


Thanks Jeff, so no other way to prevent it form building up ? so we have to bring to to dealer and clean once in awhile ?
Unfortunately none of those methods will help prevent carbon build up in a direct-injected engine. Fuel never touches the areas where the carbon build up occurs. That's the whole issue with the IS250 to begin with. Running fuel cleaner, better fuel, pushing the engine harder will all have little to no effect on how the carbon will build up on the valves.



That's definitely true, but some engine designs are more prone to excessive carbon build up. The IS250 is one of them, unfortunately.

Jeff

Originally Posted by MWIS350

I would trade it in for IS350 or IS-F now. Two year from now it won't worth much.

Originally Posted by RandyIS250

Signed i just got the car for more than a year, took me long enough to convinced my wife, i have 2010 IS model though, man if i tell her i want a better Lexus IS i think he gonna kick me out lol My wife likes 2 doors Coupe like that BMW Series 4 that was she wanted, i had enough with 2 doors i want something like Lexus IS. thanks for the advice bro. Happy Wife Happy Life !

Originally Posted by ajfinoak

Is there any type of trend as to approximate mileage when folks have had to go for the full engine rebuild? I have a 2008 with 52,000 miles on it and have had a few isolated incidents perhaps twice a year where the car will idle rough at a light for a few seconds and then return to normal. Never did get a check engine light so I don't think Lexus will do anything about it. My car will be nine years old in November thus it will no longer be covered after that. I was thinking I might sell it then but really would like to put off getting another car for another at least one year and don't really drive this one a lot anyway. I would hate for the warranty to end and have to pay for a $4000 repair on a car that will then still be worth about the same amount of money as before the repair.

Originally Posted by SC3coupe

I think you just need to have the head taken off to clean the valves, or even just from taking off the manifold and scraping and blasting. Neither should cost $4000

Originally Posted by RandyIS250

SO there is no other way to prevent it from building up Jeff ? we have to bring it to dealer or cleaning ? IS350 AWD is so rare in Toronto there is couple but the price is ridiculous expensive and it makes me rather go for 2014 model and right now i can't drive too new car i don't have parking, downtown Toronto is so ghetto i don't wanna park it on the street, dam carbon eh

Originally Posted by CassieB

I encountered the problem this weekend. My VSC and check engine lamps illuminated and the car went into safe mode while traveling on a main highway. It scared me and I am glad I did not wreck. The dealership diagnosed it as engine misfire and possible carbon build up problem. I began a claim with Lexus today since I am about 5 months past the 9 year extended warranty. Has anyone had luck getting Lexus to offer goodwill and cover if a little past extended warranty period?

Originally Posted by firelikeiy

How many miles do you have? I'm approaching the 9 year mark on my car and trying to decide what to do. I already have the cam gear rattle (which oddly seems to have gone away by using marvel mystery oil which I never use anymore but decided to try on a whim). Do you use top tier fuel? I had a Camry that I sold with 267k miles on it. I only used top top tier fuel and Chevron Techron concentrate additive. I had the fuel injectors benched tested at 265k miles and three flowed 100% with the fourth at 98%. Good stuff. Probably won't help the valve buildup I guess.

Originally Posted by jgarrido

Jeff ,Install an oil catch can is good?

Originally Posted by Jeff Lange

To know for sure you'd have to have 2 of the exact same cars, ideally from new, one with the can one without and drive them identically (or close to it) in the same regions and then compare the carbon build-up to see if there is a difference.

That said, it certainly won't hurt, and it very well may help, so I don't think they're a bad idea at all.


and what does WOT mean ?
Jeff