stops running 1990 xjs v-12

starts and runs but when it hits normal temp it shuts down, no spark or electric going to coils. sits for awhile it will run but shuts off before a mile or two, getting fuel.why? It only has 34,000 miles. Well maintained.

What makes this problem better or worse?

nothing

How long has your 1990 Jaguar XJS had this problem?

within the last week