UK Car Repair: 1989 xjs, faulty computer, pressure gauge

Question
I have a 89 xjs that starts up a runs great for about 5-10 minutes. Then it just dies as if ignition stops. After about 45 minutes car starts up and runs great again for a few minutes. I already replaced fuel pump,fuel regulators, fuel filters.It does not seem to be overheating. Any advice?  P/S I see that you have answered similar questions in the past.How does one view your COMPLETE ANSWERS on past questions?

Answer
Well, you have already done a lot of work.  When it refuses to start, have you checked for a spark at the plugs?  Ordinarily, when faced with this type of problem a pressure gauge is fitted into the system to see what is happening, it is still worth doing that. Many times your type of fault is caused by a faulty computer -usually losing the trigger feed to the injectors- the only way to tell is to go through the tests and eliminate everything else.  As for past answers,the host site can probably tell you how to access them.