I know old thread, but to respond to Joc, I'm also having idle surging issues at low THROTTLE. Idle is fine, no codes being thrown. Revs its **** off no problem.

I wanted to be sure before changing either the cable or the throttle body and there seems like there's no way to really find out unless it dies, or you do it anyway.

either way it's about $1000USD for both the engine harness and Throttle body, and that's the cheapest I've found so far.

I'd probably live with it until a code gets thrown out or it gets worse.

 

I had this off and on and then it wouldnt correct itself one day. After you check to leaks to no avail, put some stabilant 22 http://stabilant.com/techt02h.htm on the TB connection and order the wires (info Ruh Roh Raggy - P0120 )from mbpartsworld (Mercedes-Benz of South Atlanta) as they internationally ship. It is cheaper than replacing the harness and much cheaper than MB AU. (one wire from Melbourne Benz is $28 and 3 weeks from Singapore).
Throttle bodys are $400-500 on ebay and used very cheap. We share the same TB as w211 E55. There are heaps available if you want to isolate the fault. My bet is its the cable, vacuum leak or fried pentameter in the accelerator pedal (I have a new one available as I bought the wrong one - mines an 01-02 model the pedal I bought is 2113001304).
Good luck,



Happydays....

 

thanks for that, I pulled the TB off and cleaned and oiled the gears just to get a few more out of it. Jerk improved on cold start up. It's a ticking time bomb, I'll bite the bullet and order both the TB and Cable. I don't want to be stuck in the middle of the road with no throttle response.

 

Do we really need 2 of them???

IGNITION CABLE.
Required: 002
RECIRCULATI NG AIR ACTUATOR/DRIVE-BYWIRE SYSTEM POSITIONER$120.00