michael22

Hi friends!

I was hoping you could help me out. In the last week or so, I've been experiencing a terrible idle intermittently, the last two times happened on hot days (not sure if this is a factor?)

It only happens when I am stopped at a red light. Once I get going the car is smooth. If I let off the brake a little I can feel the car jerking forward which is dangerous. I have used injector cleaner and have cleaned my MAF sensor with no luck.

I really hope this is not carbon build up, because I am located in Australia and there is no carbon buildup recall here ...


Please help!

jr4div2

Given it's a 2006 IS250, I think your instinct is correct. Looking at that tach fluctuating is indicative of everything I've read. You can wait until you start throwing codes and maybe get some sympathy from your dealer, but a good intake-valve cleaning is definitely in need.

cotswold

Mine was doing the same thing, it was carbon build-up. If you live near a dealer they do have a fix. Best of luck !

MikeyK02

iTrader: (7)

Yep carbon build up. Find a shop that can walnut blast ASAP (bmw or subaru)

Aspect

IS250 rough idle = carbon buildup 99% of the time

DVS

I have the same on my 2012 model which that year the carbon issue was resolved supposedly. It feel like the car is going to die out idling when coming to a full stop. It comes on once a while....so hard to prove to the dealer.....

jr4div2

The carbon issue was never "resolved", but supposedly they made some changes to pistons or something to reduce buildup, but carbon buildup is ineveitable in an direct injection engine that has not ancillary port injection to wash the intake valves. Curious. How many miles on your car and what fuel do you use?

Mrfix

Not a lot of folks understand that. Even the Fords, VW's, Audi, GM, etc all suffer from it. They are slowly adding the $600-$1800 dollar service as regular maintenance. I think if I remember correctly I saw some new models being outfitted with aftermarket oil catch cans (Mustang and Vette). A friend who works at an Audi Dealership told me that carbon buildup pays something like 12 + hours ($140/hour) and it requires taking apart a good chunk of the engine and vehicle (they don't do walnut blasting).

The wonders of DI....If I didn't have both systems in my IS350 I would have bypassed the whole PCV system and vented into the atmosphere to try and prevent it. I don't know, perhaps it's just better to try and avoid DI altogether if you can or the second you get the vehicle home from the dealership install a catch can.

Ericspyder

Hi,
I heard a lots about carbon build up. Is it only happen with IS model or with other Lexus model also? What is the best way to prevent that? Or someway to slower it down to be happen?
Thank you.

Eric

jr4div2

It is a problem with any direct injection engine that does not have secondary port injection to clean the intake valves with fresh gasoline. It is not just Lexus either. It is a problem only with the IS250; not the IS350 as the IS350 has secondary port injection. The best way to reduce the buildup is to use top-tier fuel (google it) and synthetic NOACK oil. Some people claim a catch can bolt-on reduces it, but I have not seen anyone provide definitive proof that it works. Also, you want to make sure you occasionally run the engine hard and running temp to use the heat to help burn off some of the crud on the intake valves. Do not baby a DI-only engine or you're asking for carbon. These are all things I have read here and I do not have experience or evidence that this helps, but it makes sense based on the input from a lot of experts on this board and other internet readings.

Ericspyder

Thank you for the info.

MatthewMM

This is a known issue and Lexus changed the engine design in 2013 to have have manifold injection when the car is cold.

"December 8, 2015 MANUFACTURER COMMUNICATION NUMBER: L-TT-0192-15
Components: ENGINE AND ENGINE COOLINGNHTSA ID Number: 10152274

Manufacturer Communication Number: L-TT-0192-15

Summary: TT: Some IS250 and GS300 vehicles may exhibit one or more of the following conditions:

? MIL ?ON? DTC P0300, P0301, P0302, P0303, P0304, P0305, and/or P0306.
? Intermittently runs rough after coming to a stop with the engine at operating temperature.
? Intermittently runs rough with engine misfires present after a cold soak startup.
NOTE: The recommendations in this document apply to an intermittent misfire concern. If a vehicle exhibits a steady misfire, the root cause is not related to the referenced service bulletins and the repair manual should be referenced for diagnosis."
https://www.nhtsa.gov/vehicle/2006/L...Communications
https://static.nhtsa.gov/odi/tsbs/20...52274-9999.pdf

My symptoms are also I get MIL, and VSC disabled lights. I used "OBDLink MX+ OBD2 Bluetooth Scanner for iPhone, Android, and Windows" (available on amazon) to pull codes and data logs: RPM, location Coolant temp...

I also forwarded the case to https://www.krinsklaw.com/contact and https://mccunewright.com/contact-us/ who have had class actions against Lexus and Toyota.