I stand berated!

However, in my defence, the car had already been fiddled with by the owner and his freind, So I wasnt too sure about the reliability or relevence of fault codes so i was going back to basics (as it were)

The owner was convinced that it was a coil issue (Mercedes had replaced 5 packs six months ago at HUGE expence and he had tried replacing the sixth one, no doubt pulling various leads off in the process to find the, alledged, dud cylinder)

In my hour "slot" i was able to establish that the coil was OK and that the compressions were OK (the plugs on the affected cylinder had obviously never been "fired". though they seemed a bit oily (though not enough to cause a running problem I would have thought) hence the compression check-just in case!)

I was unable to find a switching trace on the relevent injector but then went on to find that I did get one, but only for the first 15 secs or so, after that the switching stopped and the trace "Flatlined"

During this time, the engin misfired. Sugesting to me, that the injector was not flowing fuel, despite being switched, due to some internal fault.

However, I will let you know how I get on tomorrow

(Picoscope is My Freind!)

Paul