Started the Jaguar today and it's idling fine now for some reason.
Went to Harbor Freight and picked up a
Basic Fuel Injector Service Kit so I could measure the fuel pressure with the key on, and then with the engine running.
When I got home I discovered that Jaguar apparently did away with the Schrader Valve on the fuel rail after 2003. Sum Bitch!!
So..... not sure how I'm going to check the fuel pressure. My guess would be to disconnect the hose going to the fuel rail in the middle of the photo, and somehow insert the T-fitting that's in the kit in between there to connect the pressure gauge.