Spent some time today diagnosing the misfire on kitty (XJR6 X300'97 - last of the real jag straight 6's) and amittedly the lack of spare time means that it has been a while since I last looked at it. Because of this i started from scratch with the diagnostics.
In Park - misfire is present through out the rev range and the engine is lumpy on idle despite high revs
In Drive - misfire is all but gone, revs drop to normal
Regardless of gear the engine responds perfectly to the accelerator, can take a while to come back down.
At idle:
Pulling plug leads one by one I saw that cyl 2 was the one misfiring.
swapped dis pack with anoth cylinder = no change
swapped plugs = no change
removed ECU and traced wiring back = no wiring issue
removed MAF plug = no change in revs
The last work done was changing the ICV Stepper motor but I havet driven her since.
So, my thoughts are now either air leak, faulty MAF or Ineed new injectors