E230 misfire problem

[NMears]

I have a strange problem with my E230, automatic, 1997 estate.

The car runs fine until it goes over 60 miles and hour, then it seems to misfire. The car jolts and the rev counter jumps slightly with each jolt. It seems to do it when its cruising at 65 or higher or when its accelartaing.

One garage diagnosed it as the air mass meter, changed that and it was still the same. Another garage changed the petrol filter which reduced the problem quite a bit, I would say that its 75% better than it was. Can anyone suggest any other solutions to this problem?

Thanks very much

 

[Aussie Nick]

You may have a tiny crack in one of the charger coils.As the car attains 100 kmph the engine warms up more with the increased energy, the crack expands slightly allowing the charger coil to earth and the spark plug is robbed of the electricity necessary to ignite the mixture in the piston.