MB Enthusiast

I test drove 2008 S550 71k on it

Drove nice on highway but in parking lot at low speed a stopped then let of brake

The car surged forward - not allot just a little - like a buck

This happened a couple of times but not every time - Car was in summer setting

Engine seemed to be running smooth and quiet

The car was hot as it had been driven 1 1/2hour to get to me
Does anyone know what could be causing this

The car was perfect other than that

Please advise as I am trying to make a purchasing decision by tomorrow

alx

Is it a one time jolt and then the movement is smooth? Almost like a clutch engagement on a manual car?

MB Enthusiast

yes like a soft popped clutch

alx

That is a software bug in the tcu. Was introduced a few years ago. There is a software fix for it. It has to do with tranny engagement after a complete stop disengages it to improve fuel economy. Mercedes calls it KID.

That or adaptations need to be reset- but it is usually the KID acting up.