Hello, I am having a ticking noise from the driver side valve cover all along the valve cover on my 09 XF S/C. The passenger side does not make the noise. Does anyone have any insight on what this might be, injectors, valves out of adjustment? Thanks in advance

 

Valves are zero clearance automatically adjusted. Ticking might be fuel injectors or a fuel pressure regulator. Jaguar uses a high pressure circulation system without the more common return to the fuel tank line.