E430 continous problem!!!

[fred_E430]

Greetings fellow MB owners!

I have a problem that nobody has yet resolved. My own mechanic, MB dealer...nobody has been able to apply a correct diagnosis to my problem.

On colder days, my foot on brake, mission in drive and at the stop light my car idles very rough. I need to put my mission in neutral to eliminate this annoying roughness. Once the accelator is applied there is no longer any vibration/rough idling. This seems to only happen on colder days and is louder in "S" mode than "W" mode. The roughness doesn't seems to appear on warmer days (for example temperatures above 50 or 55). After the engine has been turned on and off several times and after some time of driving, the roughness in drive mode and at the stop light seems to settle if not almost eliminated.

I took into both the dealer and my own mechanic that specializes in MB makes. Dealer suggests EGR valve and O2 sensor. My mechanic suggested the purge valve needed replacement. He did the job but unfortunately the rough idle is still there. (why did he suggest it anyway???)

Can anyone shed any light on this problem? Please help!!!

[frustrated101]

i have hear of this problem some what before, on cold days if you parked in a heated house garage and pulled out in some what freezing temps the would all most stall due to the sudden temp change through the intake temp sensor, your might be going bad and throwing a code like it is supposed to. you would have to check through actual values with a DAS cumputer system.
why did he change the purge valve, there was a chance it could have been sticking at times causeing the rough idle

[Crackerman]

if you dealership sugested those 2 parts did they change them? or did you just pay for diagnosis and walk away? they are more qualified then any other place to fix the car.

try new motor mounts and reset the crank position sensor.