erratic idling w210 220cdi after start

[jesse_A_M]

Hi,
When I start my e220cdi in the morning (or after some time after turning the engine off, say 1 hour or so), 8 out of 10 times the car idles erratically, jumping from 500-800 rmp, causing the entire car to shake. It almost seems one of the cylinders isn't working properly. The problem seems to have become more regular lately.

When I rev the engine above 1200 rpm shortly the problem disappears and doesn't come back while driving.

The onboard computer gives no faults. Service B is up in 5100 miles. I've been using Wynne's injector cleaner on a regular basis, there doesn't seem to be an unusual amount of black smoke and the power seems ok (maybe a bit sluggish).

Any thoughts on what this could be? I'd like to be prepared for the Stealership...

Thanks, Jesse

 

[jesse_A_M]

Update...

Instead of Wynne's I tried Redex this time, as I expected that most likely one of the injectors was not fully up to speed. First I fuelled up the car with exactly 50 liters with BP optimax, then I added the prescribed amount of Redex. After a few days and doing an occassional all out acceleration (clearing the throat), the problem seems to have pretty much disappeared! Power also seems up and the car seems quieter.

Now let's just hope it wasn't the sudden change of the weather .

Jesse