Dies when it's hot 100k miles - 1997 Jaguar XK8

no engine size told.
well there are like vast causes of this
my engine starts but stalls.
even parked in a drive way , transmission in pARK?
The macro causes are 3. (100 yeas same gas/petrol) rules
bad spark
bad fueling (even bad fuel)
bad engine (cam belt slipped) this fail trumps above.
a tech tests them all in order.(based on age, and miles) saves time.
no miles on car stated 100k 200k, 300k miles or more?
when was the last tune up (filters all, spark and belts)
not told. and matters huge.
does it fail cold and hot engine both, or can never get it hot
hot = means normal engine temp, 180f to 200f
is RPM started up, cold 1500RPM or less (or happens too fast to tell)
does engine die just as you shift to DRIVE.?
failures parked are the most easy to find, (moving fast failures hard)
tell more and get more, tell all things the engine does, in all modes of use. AND WHEN AND HOW LONG IT TOOK TO FAIL.
or hot engines turned off will not staRT (BUT CRANKS FAST)?
THERE IS A STORY HERE BEGGING TO COME OUT BUT DID NOT.

THE MICRO LIST IF CAUSES ARE HUGE.
EVEN a bad wire vast.

how soon after it starts does it stall,
1second 1 hour ? what, ?
some engines fail hot soaked, starts cold, but never hot

WHY NOT GET A SHOP TO FIX IT. IN USA AN ASE SHOP !

You don't say what make/model so I'm going to say the solenoid on top of the starter is dying. If its done more than 10 years or 100k miles then change it. You can change the solenoid separately but the main motor has done the same work so its bound to fail.

had issue with my 1997, bad computer, twice(4.0 liter grand cherokee laredo) also with a 1995 cherokee, same motor, crank angle sensors go at 80k-100k miles.

You could try having the fluid changed but beware, if it hasn't been changed in the last 100k miles or so the fresh detergent in the trans fluid can sometimes clean too well and leave you needing a new transmission. If you know it's been over 100k without a fluid change my suggestion would be to keep nursing the trans along and start saving money for a new transmission or a new car.

I believe the odometer may roll over at 100K. However, if there is a blank space for the first digit on the odometer, the driver for it may have died.

over 100k miles bad oil sending unit, bad crankshaft sensor
and you have a bad relay for the fans or the plug is burn inside get under the car and pull the fan plug it is under the driver side

A 100,000 mile tune up should include spark plugs, spark plug wires, fuel filter, if it has one under the frame(some newer cars have an in the tank fuel filter that is usually only changed when the fuel pump dies. Also replace the air filter if it is dirty and has been there over 20,000 miles. Some of the later models have coil on plug design and then there is no wires to replace. check tire pressure and the spare this also improves gas mileage.

you have vapor lock...try a fuel stabilizer...that should fix it

Ouch! you've got engine coolant in the exhaust from a leak somewhere...DO NOT run this engine until you get someone (dealer is best in this instance) to diagnose ($50-125)

Although I have never had oil consumption in that range, I recall having seen someone whining about Saturn (I HATE SATURNS) while I was looking for a potential class-action lawsuit and they were using a quart every ~ 1500 miles on a car with some 20-30,000 miles and were also told that this was 'in the right range.'
That may be an indication of wear causing oil loss so it bears close watching.

My Saturn, purchased new, dropped a rod cap at 57,600 miles after eating thousands of dollars for many other failures. I would have been glad to see a 100k on it before it died . . .