Q&A

 Master

You have covered a lot of the basics and the common Jag faults (bad coils). I wonder are the injectors not spraying cleanly? Also the timing chain tensioners give a lot of problems ( I think they were revised three times).A professional grade scan tool allows key engine sensor data to be analyzed right off the scan tool without having to do intrusive testing at each sensor.
There is a professional service called Identafix. http://www.identifix.com/info/about_us.htm They only deal with professional repair shops. They are in the Minnesota 651-633-8007 begin_of_the_skype_highlighting 651-633-8007 end_of_the_skype_highlighting. Your auto repair shop do all their diagnosis tests, and discuss your problem with a team of professional technicians great service cheap and very bright people. If the repair shop that are repairing your car are stumped this is a great service. This company only deal with automotive repair shops and don't answer questions for the general public but are an amazing knowledge base. I can't think of his name right now but one fellow there was really good with Jaguar and drivability issues with them.

 Master

Have someone check AIC motor for proper operation. Also, have exhaust checked for proper flow out. It sounds like a fuel to air mix problem or exhaust backpressure issue.