Jaguar Repair: 1988 xj6 sputtering, fuel pressure regulator, fuel rail

Question
The car ran fine for about 10 miles.  Shut if off and when restared sputtered, misfired, backfired and ran only 10mph.  Did the same thing last year.  Replaced the fuel filter and ran fine.  Put away for winter.  This year replaced the fuel pump.  Started right up and ran fine.  Took it 15 miles.  Turned it off.  Restarted and did the same thing.  Left it overnight.  Started ok reved ok but when I put it into gear,  started sputtering, missing etc.  Dropped the pipe to the converted and look inside, appeared to be ok?  Any help would be greatly appreciated. Thank you.

Answer
It sound like your fuel tank change over relay is bad. I do not know if the 1988's has one. Check to see if fuel is being pump from the fuel pump. If so, then check to see if fuel is at the fuel rail. Check your fuel pressure regulator. I do not have a manual on the 1988. I hope this helps. Go to (welshent.com) and download catolog. It will show you the location of all the parts. You can also buy a manual there. Sam.