I've got an 04 registered C180 Kompressor. I've owned it for almost two years. However, there is a persistent misfire which triggers the Engine Managment light on the dash.

The misfire is most pronounced at idle speed and idling speed drops below 500rpm beore picking up and then falling again.

I've replaced coil packs and plugs but still the problem continues. The Engine Management light will randomly extinguish on startup but then reappear for no reason. I also get error displays telling me that bulbs are out or on... I check and everything is fine.

Any suggestions please?

Thanks
Colin

 

I should add that once the revs are over 1000 - anymisfire seems to either disappear or becomes unnoticeable (is that even a word?)

Also - when the rear demister is switched on, the radio signal seems to deteriorate noticeably.

Any thoughts? Thank you.