I have a 740IL on a 06 plate with the n62TU engine.
brought the car as a bit of a gamble as it was fairly cheap. and could hear the engine was not running quite right.
Plugged it in to a generic OBD tool and fault code was misfire cylinder 4. went straight in for the usual culprit of a coil pack. swapped to cylinder one and the misfire didn't move.
Noticed it had been carpet bombed with new coil packs and the loom from the ecu had been replaced. ( there was me thinking it would be an easy fix.)
also the crankcase valves on the rocker covers both side have been replaced.
Moved the injectors from 4 to 1 and the misfire moved. and stayed on cylinder 1. replaced the injector on cylinder one and after a while the misfire came back to cylinder 4.
As a thought I disconnected the MAF and the car runs like a dream no misfires but slightly reduced in power as you expect.
Changed the MAF misfire returns straight away on cylinder 4.
Couple of questions that somebody might be able to answer
1 does disconnecting the MAF disable the valvetronics and switches to the conventional throttle valve, thinking it could be valvetronics issue or intermediate lever wear but this was only common on the earlier 4.4 engine up to 2004.
2 after being running on a misfire can the valvetronics adaptation be reset? finally found my INPA disc after changing laptops will try tomorrow.
3 the valve stem seals are leaking which I am changing this week on both cylinder heads, can this affect airflow into cylinders when valvetronics is opening valves slightly at idle ( just clutching at straws here.
Any advice would be great.