Well done 93green, I hope this solves your problem and that it empowers you to handle other issues that may come down the road.

Inspecting/testing is the way to go, only replacing parts when you know they are defective.

Good job!!

 

93greenconv, I bought my CPS from autoparts.titan1 (61949) on Ebay for $102.35. This is Standard Motor Products item #PC416. I installed this sensor in August and the car has not missed or loaded up or stalled since I cranked it up with the new sensor. The idle is perfect at 600 rpm with no slowing to 400 or smell of richness at pipes. All this after being told by 'the' Jag mechanic in my area that it was coils or plugs. I installed those with no change. Installed a new IAC stepper motor with no change. Drilled the 3/32" hole in the throttle butterfly. It quit stalling but still would slow to 400 rpm. The bright lining in this cloud is that I have new plugs, coils and stepper. Good luck with yours.
Cheers, RagJag

 

I just ordered a CPS from autohaus and have aO2 sensor and stepper motor also coming. I did remove and cleaned the CPS and reinstalled it, it seemed to make it run a little smoother, but not correctly, so I'm hoping that the new CPS,O2 sensor and stepper motor will make the difference. The funny thing is the computer never showed a code for any problem, except once for a FF44 code or one like that for a bad stepper motor. I already did all the electrical settings and was told by to mechanics that they did it also and found everything to be within specs. I can only hope that these new parts make a difference.

 

How rough is the rough idle? My v12 is not electric motor smooth at idle and seems to have a little 'burble' at idle but not one that I am concerned about. Most high performance motors seem to have an idle roughness, certainly not as smooth as a sewing machine.
What are you seeing as rough?

 

The V-12 Jaguar engine is known for one thing...smoothness. It should not be rough or burble at idle. One of the nice things about euro OHC engines is they are notoriously smooth, drop cams in them of questionable profile then the smoothness will go away at idle. "pushrod" engines however can be a little "rougher" at idle.