I agree, my car only has 26k on the clock, and i baby it...only the best oils, fuel, etc... I really think the new direct injection setup might have something to do with this...you do know there are 12 injectors on the 2IS. This mixed with low idle and detonation settings might account for carbon build up in our engines. I am no mechanic, just speculations really...hope they get a TSB out for this soon...for good customer relations i mean. I seriously have been looking at some Euro cars lately...the new Mercedes are simply AWESOME! Lexus has been slipping up lately, and I miss the old build quality style.

 

Just go WOT once in awhile. You won't have any trouble with carbon build up.

 

wow, are you actually talking about taking apart the engine to clean up the valves?

 

Has it been confirmed that AWD vibration is really caused by lowering the suspension? Is it true that lowering the suspension stretches out the drive axle which causes the vibration?

 

I don't think they took apart my engine...i mean, i hope they didn't take apart my engine...at 26k miles? I believe it was more of a additive injection process...with some kind of thorough manual cleaning. I honestly think more people should bring in their cars or call Lexus about this, because unless people say something, they will just continue to let things "slip".

 

Exactly.
but wait there's more...

 

Good thing the dealer managed to take care of this issue for you.

I've been experiencing the same problem with my 07 is250 AWD. I am on F-Sport springs, however, I've had them on since 18K miles and this vibration in "D" and "R" only became evident after the car has reached 30K on the odometer.

I do not have any issues with the car shaking after take off or anything like that.. It's only when my foot is on the brake pedal and the car is either in "D" or "R". It's getting pretty annoying.. I feel it in the brake pedal, doors... time to pay my dealer a visit

 

how big or obvious is the vibration ?
i do notice some vibrations in my car now but i don't think it is a problem ...yet
should there be no vibrations at all?

 

does anyone know the type/brand of fuel system treatment lexus uses?

 

I brought my '08 250 wiith 18K miles to dealer last month and they witnessed the idle vibration in steering wheel when in D with no a/c on. I had brought it in for this 2X before. By coincidence, the Regional Factory Repair Rep was there. They did top engine cleaning, , cleaned throttle body, checked fuel for water, inspected motor mounts, subframe and exhaust, checked for vacuum leaks. Still does it but they say vibration is below what other IS's do. I am not satisfied as I have not driven another that does this and the car did not do it when new. I have noticed that the vibration goes away when headlights or a/c is on as idle kicks up. Idle is at 500 or under 600 when vibration occurs. Dealer says idle is not adjustable. Any suggestions?-VERY frustrating. I also have a 10 year old Acura CL that I enjoy driving more at this point!

 

did they ever get this fixed for you? what happened?

 

No, the car is still vibrating in D at idle unless I have the headlights or A/C on. I am really disappointed in the car. I did have a '10 IS250 loaner last time I brought it in and did notice a very slight vibration under the same conditions on a new car but obviously, at least in my car, it has gotten worse as the car has gotten older (20K miles now). I will likely deal with Lexus corporate again when I bring it in. Not sure why some cars do this more than others. I don't run it often at WOT since no point in wasting the gas in San Fran Bay area traffic. As folks run out of warranty on these cars not sure what Lexus will do for those encountering this the first time or repeated. In my case, at least, they have not been able to do a lasting fix under warranty.

 

The build up is due to direct injection not spraying gasoline onto the valve (with detergents in the gas) to clean up the crank case fume sucked back into the intake from the PCV valve. This is common on many direct injection engine. If you spray a can of carb cleaner (or seafoam) into the intake manifold on a regular basis, you should be fine.

 

Quick question on carb cleaner / sea form... wouldn't that be harmful to the engine or seals ? I was told most of the third party chemicals may be too harsh on the engine and seals... such as fuel injector cleaners, etc.

 

If WOT keeps the carbon off, my valves must look like they were polished!

Koz