Hmm... What about the "front water temperature sensor" - That was causing the engine to just stop, and afterwards hard to start. - Here, the computer don't gave an error... But you was right! - Changing the sensor, and that error was gone...
Could it be the same at this point?
Sure, the computer can only tell about errors which are obvious to it. I'd think, however, that a MAP sensor fault would be easier to detect than a sensor mis-read.
Could there be any air leaks in the manifold? You must have had it off the engine a few times now.
But since you've been through literally everything, I think you need to check the valve timing. You say the timing belt has been checked, but are you certain the timing is right? It is easy to get it wrong if the engine wasn't taken out when the belt was replaced, since it's not possible to lock the cams with the engine still in-situ.
I know of at least one case, where this has been a problem. And that had even been serviced by Renault. There's no easy way to do the check, I'm afraid, except to take the engine out and redo the belt.
Colour of the tips of the plugs may give an indication, though. There are seperate cams front and rear banks, so one could be right and the other wrong, so you need to check all six. Mark the plugs where they come from and take good photos of the tips with a good camera able to focus in close distance - it might tell us something.
The car I mentions above was fixed by Autohjørnet in Espergærde. Their mechanic Torben might be able to recognise the problem if he takes your car for a test drive.
/Anders