Al MB

When the outside temp is below 5 oC the engine will intermittently drop about 200rpm at idle (enough to rock the car) when the engine temp is between 40-60 oC. As soon as the engine is at normal operating temp the problem goes away. If the outside temp is mild the problem doesn't occur and the car runs and idles perfectly at all other times.

The MAS and coolant temp sensors have been replaced and the injectors checked. There are no fault codes showing.

I'd be grateful for any advice regarding what else may need to be checked/replaced.

Regards.

MBTECH2003

Probably glow plug related, but cant do much for diagnosis on the internet.