Merc 270 CDI - Al 42
I have a strange problem which I'm not sure how to resolve.

On cold mornings(only when temp is below 5 degrees C) my car has an intermittent misfire on tickover with the revs sometimes dropping quite harshly untill the temp gauge gets to about 60 degrees when the problem suddenly goes away. It's very noticable when sationary in traffic or when idling for a long period of time. The car is fine in all other respects and runs perfectly when warm.

My local dealer says they can't detect a misfire (although I don't think they ran it long enough) and that there are no fault codes showing. They did say there was a slight vibration at tickover but it was nothing to worry about.

Grateful for any advice.
Merc 270 CDI - Screwloose
Al

Difficult to be precise without full car and year details; but the engine management's coolant temp sensor would be my first check.

Other possibilities are tappet-jacking from the wrong [too thick] oil; faulty pressure control solenoid and a worn secondary fuel pump.

Merc 270 CDI - Al 42
Many thanks for the advice. The car was recently serviced with Mobil 1 so I think the oil is ok but I'll certainly mention the temp sensor and pressure control solenoid to the dealer.
Merc 270 CDI - Armitage Shanks {p}
Staggering that you can come to the Backroom and get good information and advice (as always) and then use it to go back and tell the dealer what may be wrong with your car! He should be telling you what might be wrong! There again, it is a Mercedes dealership, so no surprises!

 

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