acceleration hesitation at low speeds,2003 C230
 

My new C230 Kompressor Sport Sedan has a very noticeable flat spot in the acceleration when coming from a dead stop or when just accelerating from slow speeds. Often, between 5 and 20 MPH, while accelerating, it acts as if you had just taken your foot off the accelerator. When you work the pedal up and down, it finally "catches" up and resumes accelerating. I have two of these cars, so it is not associated with any goofy thing that I am doing because it only happens with this car. It is now in the MB shop for the third time. They can't find the problem because it apparently doesn't show up on the computer. Any ideas or similar problems that were remedied?

do you also have a hard start and a hesitation/stall on acceleration?
m

Hesitation
 

No. It starts fine. I just have the throttle dying during acceleration. It happens probably once every 5 lights or stopsigns. Initial acceleration is usually OK, then at some point it just goes flat as if you turned the key off, then recovers itself in a few seconds. I am wondering if it might be something related to a component of the "fly by wire" system.

Driller, I am not familiar with your car, but a hesitation is either not enough fuel or weak ignition, I would test for one or the other, these can be very difficult to track down, I am trying to find mine as we speak.
good luck
m

My first guess also would be the AMM (air mass meter). It also could be any form of air leak. These motors adapt so well that even a car with AMM detached runs pretty well. I know this from finding such a hesitation in an E430 while changing the AMM. I just knew it had to be a AMM and when I went to replace it the rubber flexpipe was noted to be separated from the hard plastic breather tube. In essence the AMM could have been in the trunk.

The car actually drove pretty well except on sudden accel or extended hard accel. A new pipe fixed it.

The only real diagnostic help here are adaptation values.

MB dealers have started flashing ME-SFI control modules with new software. Several models can be up-dated for various problems. I can't remember off the top of my head if the 203 Kompressors are affected, but I'll check first thing Monday and let you know.

Flat Spot
 

Thanks. I appreciate all of the suggestions.

Driller