I see. Thanks a lot.
The car misfires with the O2 sensor off as well as with the EHA off. The smoke also remains the same. There seems to be no difference. I will now try unplugging the coolant sensor. Is the coolant temp sensor also known as a coolant temperature switch? Since there is no difference with the EHA off, could this be pointing towards a mechanical fault such as the distrbutor or fuel pressure regulator?

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With Regards