Jaguar Repair: 1987 xj6, fuel pressure gauge, timing light

Question
sorry to do this again' but your answer did not post!my 87 jag starts fine but it revs up and down in park.when driving it loses power when i give it gas then dies.it will start again and if i rev it up it will stay running a while,but then it does it again!it sat up for 7 months.your help is greatly appreciated!thanks for your past help.

Answer
William, You need to run a compression test, test the fuel pressure and monitor the ignition.

Compression should be 125 to 180 PSI and little difference between cylinders.

You need to set the timing and leave the timing light on and tape the trigger down and place the light under a wiper arm so you can watch it.

Then put a fuel pressure gauge in a "T" just before the rail and monitor fuel pressure at the time of failure. (32PSI+)

One of these will net you which has failed.
Let me know,
Howard