My brother has an XF EFI, its a SPAC, everytime he puts his foot on the clutch it dies, we have changed the start up motor and its not that. Is there any XF owners, or people who know just what this problem is and how to go about fixing it.
without more info, it'll only be a guess but the efi xf engines were really suseptible to air leaks. the draw air from the crankcase and in theory keep the crankcase under vacuam while the engine is running. if the engine has any oil leaks u can bet u'r bottom dollar it's sucking in air thru the leak while it's running.
u can cover the symptoms by richening the running mixture which is done by adjusting the polewheel inside the air flow meter - but thats cheating
Check out the throw out bearing on the clutch fork. Just an idea but if its dead and it is causing too much friction then it may be loading the motor down. Seems a bit of a long shot but its the only thing that I can think of. Drop the gearbox and inspect the clutch fork, thrust bearing etc for damage or warpage.