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Hi, I have a persistent misfire on cylinder #4. I have pretty conclusively eliminated plug, coils, injectors, compression, or DISA as the cause. Spark plug tester indicates that there is no spark, but just on that one cylinder. 12v and ground to coil connector are good. I am not sure how to test the switching signal from the DME on the third wire, but assuming it is bad I opened up the DME in the vague but not too optimistic hope of spotting a problem. I have uploaded a photo of what I saw. I'm no micro-electronics expert, but it seems highly likely to me that the drooping transistor (if that is indeed what it is) on the left, 4th in a row of 6, is the cause.

Has anyone seen anything like this before? Can anyone tell me the specification of that component? Is it likely that is I simply replaced it it would fix the problem?

Any suggestions as to how to proceed would be most welcome. I would prefer not to have to shell out for t a new DME.

Many thanks in advance.



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