E220 estate mis-fire

[kidda]

All,

I have a 94L E220 estate. The car is mis-firing on cylinders 1 and 4. It does not happen when first started and does not happen all the time when the engine is warm. But when it does happen, the car judders and there is a lack of power in the car. It has spent 3 weeks at a specialist where all the obvious items such as leads, plugs and ECU/HFM have been changed.

The head gasket was changed about 2 months ago as it was leaking. Could the problem be related to this as it did not have the mis-fire problem before? I think it will turn out to be an electronic fault but, we just cant seem to find it.

Any help will be great.

 

[grober]

Might be that disturbing the wiring loom during the head gasket replacement has meant that the wiring insulation has been damaged . It can go brittle due to heat in the engine compartment . This is a known fault on the w124 series of this age :? . There are numerous posts on this. If you examine the loom for this , you might have to slice open CAREFULLY!!! some of the bigger sleeving to see it properly, it should be obvious. Fragments of hardened insulation and bare wires. This is only a possibility and not necessarily the fault in your case PS I have also heard that either of the 2 ignition coils mounted under the inlet manifold can also go faulty. these have probably been checked but maybe an intermittant fault/short?? The article I read also said that if allowed to continue that a faulty coil could damage the ECU unit!! so might be worth checking out by substitution. GOOD LUCK.