imgoingbarmy

I have a C200, w202 1996 which has developed an intermittent fault. From cold it starts but come the first junction where I come to a stop, the engine becomes lumpy and cuts out. it may do this three or four time from then on but then clears and is fine from then on.

I have spoken with my usual garage, another 'trade' friend, even independent Merc dealers and none have any ideas.

It has been suggested that I should use a main dealer and pay around £150 to have then plug into the ICU. However, no-one seems to think it will disclose the fault, only give an idea.

My question is simple - how accurate would the MB dealership diagnostics be with my vehicle

mleskovar

If they caught it in the act of failing it would probably be accurate. Otherwise, if the motor is running properly, there would be little chance of finding the problem. Intermittent problems are always hard to find. £150 seems overpriced for a diagnostic scan though.

lkchris

A just-started (cold) engine has to run rich for a bit.

In the old days this was called "choke" but the concept is still valid and is still implemented, albiet with electronic control.

Sounds like yours stops being rich too soon. That is, before engine is sufficiently warmed up.

This could be a vacuum leak or some electronic problem involving the sensor that measures temperature or the components that create rich mixture.

redcoupe

It sound line the vacuum line going to the brake booster has a bad check valve in it.