+1

There are threads about bad injectors leaking and causing a backfire that can crack the intake manifold.
This is classic vacuum leak symptoms.

 

To the OP:

I was experiencing the same problem described in your post. Random bucking/surging at idle, the car ran fine above 1000 rpms. I took the car to my mechanic and they could not replicate the problem. One month later, car was due for service and I had all the plugs and wires changed. Problem solved. Car now runs like new.

Good luck.

 

Issue finally fixed...

After changes to ECM (they then had to put the old one back in at no charge because that was not the problem), plugs, Ignition cables... etc... which helped somewhat with the bad bucking at the light... final issue (missing/shudder while idling) was resolved by EGR valve.. replacement.

Technically the car was at the dealer from April 11th until May 4th!

Thanks to all... Just glad I have it back. My biggest dissapointment in the whole process was the dealer was in a hurry to discharge the car after bucking was fixed but the rough idle was not... I think I burnt some bridges there... Service Manager did jump in and save the day in the end.

This has been a nightmare...

 

good to know, my indy mech, which had me replace every other part on the car, insists its not the egr valve...egr valve doesn't work that way...

hopefully this fixes my issue so i can throw the old egr valve in his face

 

thats cool that you got it fixed .. aND got the car back !!!
Desired speeds , changed his out and it still does it .. not sure if i should pick one up or not now ..

 

Congrats. Bad EGR valves are just like big vacuum leaks. A simple vacuum gauge on the manifold would have found it long ago. Unbelievable that the dealer could not find the problem sooner with the symptom manifesting constantly. What happened to good old know-how?

Too bad. I suggested the vacuum be checked back on May 2nd. Apparently they did not do this.

 

Craftsmanship is long gone at a lot of dealerships...and my friends and family wonder why I work on my own cars???
To the OP: Glad that you got your car back, and it's repaired correctly (finally).

 

lucky you! i wish your solution applied to my car too.

 

I had the same problem .they couldn't find any thing wrong so i decided to try fixing it my self with a bottle of mass air flow sensor cleaner it worked for me,i took it all the way off the car cleaned it and blew it out with a air hose,hope it works for you

 

There was an old(real old) technical bulletin regarding 2000 and 2001 E55s that would buck when coming to a stop. You basically have to two foot the car to keep it running. It will not throw codes, so you won't be getting a check engine light. If I remember correctly, it gives an affected ECU part number, and that the remedy is to replace the ECU.


Nick

 

you know what I found interesting? I was in my friend's CLS63 last time and it did the exact thing my car was doing. It had a funny idle when you started it up just like my car and when I was sitting at a stoplight the car had the same roughness to it. He also mentioned that his old E55 also had this slightly rough idle. I'm pretty convinced that my car is perfectly normal. Can anybody chime in to say their car also has a certain roughness to it? Or are your cars perfectly still when sitting at a stoplight what you cannot feel the engine at all?

 

I think it is normal for the high performance V8s to do that. After driving for awhile, my car does a little rough idling when stop at a light. Sometimes I drive the car hard and the rough idling does not occur but at times it does. I never even though of anything about it as compare to my friend's E320 which is not as I kept thinking of my college days when a fraternity brother of mine had an old firebird and talk about rough idling now that thing is rough.

 

EGR eh

Interesting indeed. You would think with all the high end data equipment they would have found the issue a lot sooner than later. However problem fixed!

Welcome back

 

I've had my car 6.5 years and bought it with 16K miles on it...113.5K today. Mine idles perfectly, has the cold start-up tick...which goes away for the most part...always had it. Since I had my transmission filter changed a few thousand ago it hasn't done it much. But it will do as you say..when I come to a stop light it will jump around and you really have to hold the brake. I pop it into neutral, goose it and it settles right back down. I guess with your experience and the experience of your friend maybe it's more normal than we think. With the limited production numbers its not like there are a ton of them running around to compare.

 

Normally never post but..,
did anyone check valve springs?
I've seem them break causing OK compression at idle then when reving misfire etc..,
Good luck

 

Today I found myself replacing wires, plugs and fuel filter. Thinking that that was responsible for the rough idle at the stop and hard time starting. Turns out my egr valve was stuck open causing six out of eight cylinders to misfire, causing the rough idle. Im so glad to have my baby running good again.

 

If I ever get in there, I am going to block plate it.

 

careful with that. Some cars have timing maps that recognize EGR flow when it adjusts its timing parameters to prevent detonation.

 

Oh, I'll be careful!

 

Mine started stumbling at 3K RPM, no CEL, it turned out to be a bad spark plug wire. Replaced with magnecore wires in 2008 been happy ever since.