2004 xj8 has fuel in the rail when I push the pin, but does not have any real pressure behind it. Does anyone know how to check to see if it is the fuel pressure regulator that is causing the lack of pressure?

You need to post in the correct forum section.

https://www.jaguarforums.com/forum/x...-x350-x358-28/

You will have better luck with a correct answer.

bob