My wife's '94 XJS 2+2 with a 4.0L six is hard to start after it has heated up. After is has cooled for a few hours it starts normally. I takes 4-5 separate cranking sessions to get it to fire up and then it runs OK. This problem has been getting slowly worse over the last couple of years. If I had to guess, it would be that it is not getting enough fuel, but that's just a guess. I had heard that in a fuel injected engine there is some kind of valve or pump that sends some initial fuel to get the engine going. I have read some posts from other forums that talked about a pressure regulator and a temp sensor that could cause a problem.
Bill Bevan
bgbevan
earthlink.net