Interested in your latest find myself as an owner in Stockholm has much the same problem but on no.2 (V6) cylinder. As I understand it, there are three connectors on each coil, one a live (+) from the main relay, another a minus (-) and the third is the impulse from the ECM. Hope that’s right ?
I’d begin by removing the connector perhaps on no.3 coil, measuring what you find and compare that to your misfiring no.5.

I believe it’s safe to do this just with ignition on but car not running (?) if you want the car running you’d have to fit everything in place and pierce the insulation with a pin or something.

At the moment I don’t know what reading I should expect to receive at the third cable from the ECM , perhaps someone could enlighten us ?

Regards

Seems like it's going to end up being a duff injector.

If the cylinder bore or rings were the problem it would be blowing out smoke from the exhaust.

I will proceed at swapping the injectors no 3 with 5 too and see how that goes, however, hope I won't damage one of those cursed O rings while swapping them, had that problem before and it drove me nuts.

Also, if TOAF shows p0305 then it is definetely cyl no. 5 misfiring and not other right? I am asking this because I am not sure if TOAF counts the cylinder the way Rover did

And also, if the cylinder bore or rings are the problem, would it always be blowing smoke or only for a while after starting it up?

Seem to remember some discussion ages ago on the dark side about Toaf and counting cylinders but that was about the diesel, something about the unique French way of numbering. T-Cut might have been one of the contributors.

Will be following your progress with interest.

Regards

Just checked now and oil smells like gasoline, badly... bad sign obviously, this further tends me to think that it's the injector that's bad, spraying too much or not enough gasoline into the combustion chamber which is then not properly ignited thus what's left leaking down in the oil pan, and of course in the meanwhile creating a misfire too, hope it's this thesis the one that's valid, if the cylinder really has no proper compression then it's gonna cost a buck more that's for sure :getmecoat:

I've thought in the meanwhile of more things that could cause the matter: O2 sensors, lambda sensor, maybe even timing issues, but the O2 sensors should affect one of the engine banks that they're responsible for I guess and the latest issues I mentioned should make the whole engine misfire in a matter and make it run a little rough I guess, but neither should affect only one cylinder I suppose...

I have never known a faulty injector on the petrol engines, have a look at the O2 sensors and their wiring first.

I took the injectors off anyway and brought all of them to my mechanic to get them properly inspected and cleaned, also the small filters inside of them will be replaced together with all the o rings because they were in a really ugly shape, some of them looked like melted and had some cracks in them. This won't hurt for the car anyway and should help. Just hope that when I install them back the misfire will be gone. And even though I swapped the spark plugs, coils and leads from a good cylinder to the misfiring one and the misfire remained on cylinder nr 5, I still bought a set of 6 iridium spark plugs, and will see if the refreshed injectors and the new spark plugs resolve the issue, if not, I kind of ran out of ideas.

Some more things though:

- If the ECU is the problem, how can one diagnose that?
- What are the readings that the O2 sensors should output when they are operating normally?

Received the cleaned injectors and all of them are perfectly fine now, 2 of them were not spraying enough but after cleaning they were fine as sound. Installed them back, fired it up and nothing has changed, not even a bit, same misfire.

Although forgot to mention something from the beginning: my professional delphi scanner shows me the P0305 error code which indicates cylinder 5 of course, but in the description of the code it say misfire cylinder 2 (P0305 - Misfire cylinder 2). How could this be possible. Could it be that cylinder 2 is really the problem here?

RAVE gives P0305 as cylinder 5.

Simon