AMG2GO

Guys I need some input. When I first bought my CPO CL600 (17K miles), I noticed the engine had an ever so slight vibration. I thought maybe it was bad gas, or fouled plugs, and I let it go. A while later the check engine light came on, and sometimes the car ran as if 2 cylinders were out, a terrible misfire was evident. It shook and had NO power.

Went to the dealer, 6 coils were replaced. Drove the car again, same thing, and 6 more coils were replaced, as well as a harness to the ECU, and the ECU was updated with some software. The check engine has not been on lately, but there is still this ever so slight vibration.

I told the dealer "my 10 year old Lexus SC400's V8 is absolutely smooth... you can't tell the engine is on, at all. Why does this car have a slight vibration sometimes?" and the service advisor's response was "its a very powerful V12 you have to understand".... which made no sense, because a V12 is smoother than a V8.

What I want to know if you have a CL600 is, does the engine shake at all at idle? I am talking about a very small shake.... it all being relative.... I expect none.. but I have some. Especially cold, I can literally feel the body of the car shake ever so slightly every once in a while as if a misfire happens, but it is very minor. You have to look for it.

Is this normal? sit in your CL6 cold and start it up... look at the A-pillar and see if its absolutely still.... or is there a small shake, no matter how small at times?

Thanks

Vendetta

I've noticed an occasional slight shudder, and only at idle. There's been no loss of power, and the thing is smooth as silk at anything above idle RPM in park or otherwise. Weird though. If I get so much as a hint of a problem, I'll be all over the dealer. Needless to say, I'll be watching this thread carefully, so.......

How's about it, guys? Any roughness at idle or otherwise? May help to note model year, mine's an '01.

-V

techbike

All my CL600's been doing much of has been idling. :p
Haven't had a chance to drive it much and I'm waiting for a set of Contis, but I don't notice any hiccups or anything.

I notice this occurence more on my CLK55AMG. Actually gets rough at idle - in Neutral. When put into gear, it disappears. Same thing happens on the E430. I remember a discussion at the shop and the consensus amongst the exoticar wrenches was that because these engineers try to wring as much horsepower out of lightened motors (aka AMG, et al) you get that stumble occasionally. In the horsepower vs displacement wars, the powerband is not as wide as it used to be. This could be a product of lightened flywheels, tranny components, aluminum heads, extreme porting, aggressive cam profiles, etc. However, under load, as when putting it in gear or accelerating, the roughess disappears. We're building my autocross car (a '72 mini cooper) with an overbored block, highly modded head, large valves, big trwin carbs, hot cam, high lift rockers etc, and it will only idle at 1100 RPM, with everything rattling and bucking. But put it in gear and scream away, very smooth and pins you to the seat.
Obviously, and perhaps on the CL6, the design objectives were exactly that: smooth power under load. I'm from the old school and try to "prolong engine life" by unloading the motor when not needed, and shift to N - as when stopped at a light. Apparently, most modern drivers simply put the gear selector into D and just ride the brakes, so to speak. If I drove this way, I probably would never have noticed the idling roughness at all.

So does it do this when you're in "D" and stopped?

Jakillo

Our 01' Cl600 shakes on idle. I think its normal, i dunno.

Chas Jr

My CLk 55 shook at idle and all 5 of my CL's have also..NORMAL..

AMG2GO

I find it odd that my Lexus V8 idles smoother than my MB V12. I am glad others have it... dealer says its normal too. Thanks for the feedback guys.

Vendetta

Took my car in for routine service and had them check the rough idle. My SA said that was NOT normal for these cars. Now he tells me the car needs a new mass airflow sensor, and that's what's causing the rough idle. And that's the good news! Wait 'til ya hear about the ABC system... more on that when he calls me back (I'll put that in the "damn ABC light..." thread).

All I can say is I'm sure glad I bought that warranty!

Ciao,
-V

AMG2GO

I didn't think it was normal! maybe I need a new MAF. I will have to get together with you and compare... No joke, my Lexus V8 is smoother.

vraa

Your Lexus has the 1UZ-FE. One of the best engines ever made. I used to have a LS400

Try asking your dealer to raise your idle just a tad bit. I know for a buncha X5's the idle was set really low and the car had a rough idle.

mmgrad

'bout 2 yrs ago, i complained to the dealer that my idle was kinda rough... and they adjusted my idle rpms... same thing, still some vibration

altho, i don't know how much they adjusted it....

vraa

Two years ago I shoulda read closer.

Perhaps it is a weak motor mount?

Vendetta

Got my CL back today. New MAF and Service B done. Idles smooth as silk now. You might wanna look into it.

AMG2GO, get my email...?

-V